If you're installing Windows 7 for the first time on a new computer and you don't have any existing version of Windows to remove, upgrade, or replace, see:
Install Windows 7
To install Windows 7 and keep an earlier version of Windows on your computer, see:
Install more than one operating system (multiboot)
For more information:
Install, upgrade, and activate Windows 7
If you have an existing installation of Windows 7 that you want to reinstall, see:
Reinstall Windows 7
Upgrade from Windows XP to Windows 7
Upgrade from Windows Vista to Windows 7
Upgrade to another edition of Windows 7
Can I uninstall Windows 7?
Uninstall Windows 7 on a multiboot system
If you're installing Windows Vista for the first time on a new computer and you don't have any existing version of Windows to remove, upgrade, or replace, see:
Install Windows Vista
To install Windows Vista and keep an earlier version of Windows on your computer, see:
If you have an existing installation of Windows Vista that you want to reinstall, see:
Reinstall Windows Vista
Upgrade from Windows XP to Windows Vista
Upgrade to another edition of Windows Vista
Can I uninstall Windows Vista?
Uninstall Windows Vista on a multiboot system
If you're installing Windows XP for the first time on a new computer and you don't have any existing version of Windows to remove, upgrade, or replace, see:
Install Windows XP
To install Windows XP and keep an earlier version of Windows on your computer, see:
How to create a multiple-boot system in Windows XP
If you have an existing installation of Windows XP that you want to reinstall, see:
Reinstall Windows XP
Upgrade to Windows XP from an earlier version of Windows
You can't uninstall Windows XP, but you can install another version of Windows, which then replaces Windows XP. If you want to replace Windows XP with a newer version of Windows, see “How to upgrade” on this section of the page.
