There are two options to choose from during the Windows 7 installation process:
Upgrade. This option replaces your current version of Windows with Windows 7, and keeps your files, settings, and programs in place on your computer.
Custom. This option replaces your current version of Windows with Windows 7, but doesn't preserve your files, settings, and programs. It's sometimes referred to as a clean installation for that reason.
In this article you'll find detailed instructions for installing Windows 7 and reinstalling Windows 7.
For more information about installing Windows 7, see Installing Windows 7: frequently asked questions and Windows 7 installation problems: frequently asked questions. For more information about upgrade options, go to Upgrading to Windows 7: frequently asked questions on the Windows website.
You can buy Windows 7 at retail locations, or you can purchase a computer with Windows 7 already installed. In some countries or regions, you can also purchase Windows 7 online.
If you purchase an upgrade copy of Windows 7, you'll need to install Windows 7 on a computer running Windows XP or Windows Vista. For more information, go to Upgrading to Windows 7: frequently asked questions on the Windows website.
The Windows 7 installation disc package includes both 32-bit and 64-bit versions of Windows 7. If you download Windows 7 from the Microsoft Store, you'll need to choose either a 32-bit version or 64-bit version to download. For help deciding which version to install, see 32-bit and 64-bit Windows: frequently asked questions.
The table below lists common ways to install Windows 7, and links to more information on the Windows website.
Install Windows 7 on a computer running Windows XP.
Go to Upgrading from Windows XP to Windows 7.
Install a 32-bit version of Windows 7 on a computer running a 32-bit version of Windows Vista.
Go to Upgrading from Windows Vista to Windows 7.
Install a 64-bit version of Windows 7 on a computer running a 32-bit version of Windows Vista.
See "Installing a 64-bit version of Windows 7 on a computer running a 32-bit version of Windows" later in this topic.
Install a 32-bit version of Windows 7 on a computer running a 64-bit version of Windows Vista (less common).
Go to Upgrading from Windows Vista to Windows 7 (custom installation) .
Install a 64-bit version of Windows 7 on a computer running a 64-bit version of Windows Vista.
Install Windows 7 on a computer and format the hard disk during installation.
See "Using the Custom installation option and formatting the hard disk" later in this topic.
Install Windows 7 on a computer without an operating system.
See "Using the Custom installation option if no operating system is installed" later in this topic.
Install Windows 7 on a computer without a DVD drive.
For information about downloading Windows 7, and then creating a USB flash drive to install Windows 7, go to Installing Windows 7 on a netbook and see sections later in this topic.
To save time and help avoid problems during installation:
Find your product key. You can find your product key on your computer or on the installation disc holder inside the Windows package—or in a confirmation e‑mail if you purchased and downloaded Windows 7 online. A product key sticker looks similar to this:
PRODUCT KEY: XXXXX-XXXXX-XXXXX-XXXXX-XXXXX
Go to the Microsoft website to see examples of product key stickers.
Write down your computer name. If your computer is currently connected to a network, you might need you computer name after Windows 7 installation is complete. For more information, see Find your computer name.
Back up your files. You can back up files to an external hard disk, a DVD or CD, or a network folder. We recommend using Windows Easy Transfer to back up your files and settings. For more information, go to the Windows Easy Transfer webpage.
Download and run the free Windows 7 Upgrade Advisor. It will help find any potential compatibility issues with your computer's hardware, devices, or programs that might affect installing Windows 7. For more information, go to the Windows 7 Upgrade Advisor webpage.
Decide whether to install the 32-bit or 64-bit version of Windows 7. The Windows 7 installation disc package includes both 32-bit and 64-bit versions of Windows 7. If you download Windows 7 from the Microsoft Store, you'll need to choose either a 32-bit version or 64-bit version to download. For help deciding which version to install, see 32-bit and 64-bit Windows: frequently asked questions.
Update your antivirus program, run it, and then turn it off. After you install Windows, remember to turn your antivirus program back on, or install new antivirus software that works with Windows 7.
Connect to the Internet. Make sure your Internet connection is working so that you can get the latest installation updates, such as security updates and driver updates that can help with installation. If you don't have an Internet connection, you can still install Windows 7.
The Upgrade option keeps your files, settings, and programs from your current version of Windows. To learn more about which versions of Windows can be upgraded to Windows 7, go to Upgrading to Windows 7: frequently asked questions on the Windows website.
If you use a fingerprint reader or other biometric device to log on to your computer, write down your password before upgrading. You must log on by typing your user name and password the first time that you use Windows 7 after upgrading.
Some programs such as Windows Mail and Outlook Express are no longer included in Windows 7. If you used Windows Mail or Outlook Express as your e‑mail program, you'll need to install a new e‑mail program after you finish installing Windows 7 to read your messages or to send and receive e‑mail. For more information about programs you can use, go to Looking for Windows Mail? on the Windows website.
Turn on your computer so that Windows starts normally. (To perform an upgrade, you can't start, or boot, your computer from the Windows 7 installation media.)
After Windows has started, do one of the following:
If you downloaded Windows 7, browse to the installation file you downloaded, and then double-click it.
On the Install Windows page, click Install now.
On the Get important updates for installation page, we recommend getting the latest updates to help ensure a successful installation and to help protect your computer against security threats. You need an Internet connection to get installation updates.
On the Please read the license terms page, if you accept the license terms, click I accept the license terms, and then click Next.
On the Which type of installation do you want? page, click Upgrade to begin the upgrade. You might see a compatibility report.
Follow the instructions to finish installing Windows 7.
If you shared any printers in Windows Vista, you'll need to re-share them by following these steps:
Right-click the printer you want to share, and click Printer properties.
On the Sharing tab, select the Share this printer check box, and then click OK.
If other computers still can't access the printer, delete the printer from the other computers, and then add the printer again.
The Custom option installs a new copy of Windows 7 on the partition you choose. This erases your files, programs, and settings.
Back up any files and settings you want to keep so that you can restore them after the installation is complete. You'll need to reinstall your programs, so make sure you have the installation discs and product keys for the programs you want to use in Windows 7, or setup files for any programs you downloaded from the Internet.
If you're running a 64-bit version of Windows and plan to install a 32-bit version of Windows 7, programs that were designed to run only on a 64-bit operating system might not work. Check the software manufacturer's website for more information, or go to the Windows 7 Compatibility Center webpage to search for hardware and software tested to be compatible with both 32-bit and 64-bit versions of Windows 7.
If you don't format your hard disk during installation, data files are saved to a Windows.old folder on the partition you installed Windows 7 on. However, you should still back up your files. If you have data files that are encrypted, you might not be able to access them after installing Windows 7. If you've backed up your data files and then restored them after installing Windows 7, you can delete the Windows.old folder.
Turn on your computer so that Windows starts normally, then do one of the following:
On the Install Windows page, follow any instructions that are displayed, and then click Install now.
On the Which type of installation do you want? page, click Custom.
On the Where do you want to install Windows? page, choose the partition containing your previous version of Windows (this is often the computer's C: drive), and then click Next.
In the Windows.old dialog box, click OK.
Follow the instructions to finish installing Windows 7, which include naming your computer and setting up an initial user account.
Formatting your hard disk during a custom installation of Windows 7 permanently erases everything on the partition that you are formatting, including your files, settings, and programs.
If you're using an upgrade version of Windows 7, don't use a program from another software manufacturer to reformat your hard disk before installing Windows 7. Instead, follow the instructions in this section.
To format your hard disk during Windows 7 installation, you'll need to start, or boot, your computer using the Windows 7 installation disc or USB flash drive.
Turn on your computer so that Windows starts normally, insert the Windows 7 installation disc or USB flash drive, and then shut down your computer.
Restart your computer.
Press any key when prompted, and then follow the instructions that appear.
On the Install Windows page, enter your language and other preferences, and then click Next.
If the Install Windows page doesn't appear, and you're not asked to press any key, you might need to change some system settings. To learn how to do this, see Start your computer from a Windows 7 installation disc or USB flash drive.
On the Where do you want to install Windows? page, click Drive options (advanced).
Click the partition that you want to change, click the formatting option you want to perform, and then follow the instructions.
When you've finished formatting, click Next.
If you're using the upgrade version of Windows 7 on a computer without an operating system installed, you might not be able to activate this type of installation. The upgrade version requires Windows XP or Windows Vista to be installed on the computer to activate Windows 7. During setup, you need to leave the product key box empty. To activate Windows 7, go to the Microsoft Support website. For more information, see Windows 7 activation error: invalid product key and Windows 7 activation error: 0xC004F061.
The Custom option installs a new copy of Windows 7 on the partition you choose. This erases your files, programs, and settings. If there are any files on the partition, back them up before proceeding.
To do this, you'll need to start, or boot, your computer using the Windows 7 installation disc or USB flash drive.
Turn on your computer, insert the Windows 7 installation disc or USB flash drive, and then shut down your computer.
On the Where do you want to install Windows? page, choose the partition that you want to install Windows 7 on, or click Unallocated Space if no partitions are listed, and then click Next.
If a dialog box appears saying that Windows might create additional partitions for system files, or that the partition you chose might contain recovery files or other types of files from your computer manufacturer, click OK.
Before you begin, make sure that your computer can run a 64-bit version of Windows. For more information, see 32-bit and 64-bit Windows: frequently asked questions.
You can reinstall Windows 7 using Recovery in Control Panel, under Advanced recovery methods. This method reinstalls Windows 7, either from a recovery image provided by your computer manufacturer, or from your original Windows 7 installation files. You need to reinstall all of the programs that you added, and restore all of your files from a backup. For more information, see Choosing an advanced recovery method.
If Windows 7 doesn't run at all, you can reinstall Windows using your original Windows 7 installation disc. To do this, follow the instructions in "Using the Custom installation option and formatting the hard disk" earlier in this topic.
Back up your files before you begin reinstalling Windows 7 if possible, even if you're reinstalling Windows 7 on a hard disk partition, and you have personal files on a separate partition. For example, if you have encrypted files, you might not be able to access them after reinstalling Windows. A custom installation replaces the current version of Windows 7 and all personal files.
To learn how to activate Windows 7, see Activate Windows 7 on this computer. For more information, see Activating Windows 7: frequently asked questions.
Article ID: MSW700061
In this article you will find instructions for:
Upgrading to Windows Vista when you already have a version of Windows XP Home Edition or Windows XP Professional on your computer and you want to keep your files, settings, and programs.
Installing a new, or clean, version of Windows when:
You want to replace your current operating system.
You want to install Windows Vista on a separate partition of your hard disk, and you have an operating system on your computer and an available partition.
You have a computer with no operating system installed.
Reinstalling Windows Vista when you want to restore default Windows settings or when you are having trouble with Windows and need to reinstall it by performing a clean installation.
For more information about whether you should upgrade or perform a clean installation, go to Upgrade paths from previous versions of Windows on the Microsoft website.
During the installation process, you will need:
Your Windows installation disc (DVD or CD).
Your Windows product key (25 characters). You can find your product key on your computer or on the installation disc holder inside the Windows package. A product key sticker looks similar to this:
Go online to see other stickers.
The name of your computer. You will need to provide this if your computer is currently connected to a network. If you're using Windows XP, here's how to find your computer name:
Click Start, right-click My Computer, and then click Properties.
The computer name is displayed on the Computer Name tab.
You will also need to decide whether to install a 32-bit or 64-bit version of Windows Vista. For help deciding, see 32-bit and 64-bit Windows: frequently asked questions.
For more information about installing and upgrading 32-bit and 64-bit versions of Windows, go to Installation choices for Windows Vista (32-bit) or Installation choices for Windows Vista (64-bit) online.
Before installing Windows, be sure to disable all antivirus software and back up your files to an external hard disk, a DVD or CD, a USB flash drive, or a network folder.
When you upgrade to Windows Vista, you keep your files, settings, and programs from your current version of Windows.
Important: Use the following procedure only when upgrading from a 32-bit version of Windows XP to a 32-bit version of Windows Vista.
Before you upgrade:
Check your hardware compatibility. Go to the Windows Vista Upgrade Advisor on the Microsoft website. Alternatively, you can run the Windows Vista Upgrade Advisor during the upgrade by clicking Check compatibility online on the Install Windows page.
Make sure you have Windows XP Service Pack 2 installed before you upgrade a computer running Windows XP to Windows Vista. If you're using Windows XP, here's how to see if your computer is running Windows XP Service Pack 2:
On the General tab, verify that Service Pack 2 appears in the System area.
If Windows XP Service Pack 2 is not installed, you must install it before you upgrade to Windows Vista. To get Windows XP Service Pack 2, go to Windows Update online.
If you have an upgrade copy of the 32-bit version of Windows Vista, you must start Windows installation while running your existing version of Windows.
If you are using a fingerprint reader or other biometric device to log on to your computer, make sure you write down your password before upgrading. You must log on by typing your user name and password the first time that you use Windows after upgrading.
For detailed information about upgrading from language versions of Windows XP to Windows Vista, go to You cannot upgrade certain language versions of Windows XP to Windows Vista online.
Insert the Windows installation disc into your computer's DVD or CD drive. You must start Windows installation while running your existing version of Windows.
On the Get important updates for installation page, we recommend getting the latest updates to help ensure a successful installation and to help protect your computer against security threats. You will need an Internet connection to get installation updates.
On the Type your product key for activation page, we strongly recommend that you type your 25-character product key to help avoid problems during activation.
On the Please read the license terms page, if you accept the license terms, click I accept the license terms.
Follow the instructions.
After installing Windows, don't forget to enable existing, or install new, antivirus software.
You can use the following procedure when performing a clean installation of a 32-bit or 64-bit version of Windows Vista.
When you perform a clean installation, your existing version of Windows, including all of your files, settings, and programs, is automatically replaced. You can back up your files and settings, but you must manually reinstall your programs and restore backed-up files when the installation is done. For information about how to restore your files after a clean installation, go to How to restore your personal files after you perform a custom installation online.
Perform a clean installation if your computer has no operating system installed, or you want to delete your current operating system and replace it with Windows Vista, or you want to partition your hard disk and install Windows Vista on a specific partition.
Before you install Windows, check your hardware compatibility. Go to the Windows Vista Upgrade Advisor on the Microsoft website. Alternatively, you can run the Windows Vista Upgrade Advisor during installation by clicking Check compatibility online on the Install Windows page. If you start the installation from the installation disc, this link to the Windows Vista Upgrade Advisor does not appear on the Install Windows page.
You cannot install an upgrade copy of Windows Vista on a partition unless a copy of Windows 2000 or Windows XP is already installed on that partition. Depending on which version if Windows you are upgrading to and from, you might have to perform a clean installation.
Turn on your computer, insert the Windows installation disc into the computer's DVD or CD drive, and then do one of the following:
If your computer already has an operating system installed, and if you do not want to create, extend, delete, or format partitions, go to step 2.
If your computer does not have an operating system installed or if you want to create, extend, delete, or format partitions, you need to restart your computer with the installation disc inserted in your CD or DVD drive. This will cause your computer to start (or "boot") from the installation CD or DVD. If you are asked to press a key to boot from DVD or CD, press any key. If the Install Windows page appears, go to step 2.
If the Install Windows page does not appear and you're not asked to press a key to start from DVD or CD, you might have to specify that your computer use its DVD or CD drive as the startup device. This means that you need to set the DVD or CD drive to be the first startup device in the basic input/output system (BIOS). To learn how to do this, see Start Windows from a CD or DVD. After you select your DVD or CD drive as the startup device, restart your computer, and then start Windows from the installation DVD or CD as previously described.
If you have an upgrade copy of a 32-bit version of Windows Vista, you will see a message telling you to restart your computer and start Windows installation from within your existing operating system.
After you click Custom, if you have an upgrade copy of a 64-bit version of Windows Vista and do not have a version of Windows that can be upgraded, the installation cannot continue. You will need to install a copy of Windows 2000 or Windows XP to proceed with this installation method.
On the Where do you want to install Windows? page, select where you want to install Windows.
If you don't partition your hard disk, click Next. The installation will start automatically. You might see a compatibility report that lists which programs and software drivers won't work after the installation. You can resolve any issues after the installation is complete.
If you have an existing partition and want to have more than one operating system on the same computer, you can install Windows on a specific partition. (This is called a dual-boot or multiboot configuration.) If you do this, be sure to install Windows on a different partition from the partition where your current version of Windows is installed. To install Windows on an existing partition, select the partition you want to use, and then click Next to begin the installation. You might see a compatibility report.
If you want to create, extend, delete, or format a partition, you must start Windows from the installation DVD or CD. If you did not begin the installation process this way, follow the instructions for starting Windows from the installation DVD or CD that appear in the first step of this procedure, and then follow the instructions on each screen. On the Where do you want to install Windows? page, click Drive options (advanced), click the option you want, and then follow the instructions. Click Next to begin the installation. You might see a compatibility report.
Be sure to enable existing, or install new, antivirus software after the installation is complete.
If you want to reinstall Windows Vista by performing a clean installation—possibly to restore the default Windows settings—here's how to do it. (If you're having a problem with Windows, first see What to do if Windows won't start correctly, which explains how to use the Windows installation disc to fix problems without completely reinstalling Windows.)
Back up your files before you begin reinstalling Windows, even if you're reinstalling Windows on a hard disk partition. A clean installation replaces the current version of Windows and all personal files.
Turn on your computer and insert the Windows Vista DVD or CD.
On the Install Windows page, follow any instructions that might appear, and then click Install now.
Follow the instructions on each page. On the Which type of installation do you want? page, click Custom.
On the Where do you want to install Windows? page, select the partition where you want to install Windows.
Click Next to begin the installation. You might see a compatibility report.
See all support pages for install, upgrade, & activate.
Ask a question in the community forums.