Multibooting is a technique used to run two or more operating systems on a single computer. Some people choose to set up a multiboot computer to run older programs that require an earlier operating system to operate properly. However, multibooting can be complicated and, if not done properly, can render your system inoperable.
An easy way to enjoy the benefits of multibooting without the pitfalls is to use Virtual PC 2007. It's a free download from Microsoft you can use to install multiple operating systems on your computer, and then switch between them as easily as you switch between programs. You can download Virtual PC 2007 from the Microsoft Virtual PC 2007 website.
Virtual PC 2007 runs on Windows Vista Business, Windows Vista Enterprise, Windows Vista Ultimate, Windows XP Professional, and Windows XP Tablet PC Edition.
Multibooting requires separate partitions on your computer's hard disk for each operating system. You also need to install the oldest operating system first, which can be frustrating if you want to add an earlier operating system (for example, you're currently running Windows Vista but you want to add Windows XP). Installing an earlier version of Windows after a more recent version is already installed can render your computer inoperable. This can happen because earlier versions of Windows do not recognize the startup files used in more recent versions of Windows and can overwrite them.
Virtual PC 2007 is a virtualization, or simulation, program you can use to create virtual computers (called virtual machines) on your computer (called the host computer). The virtual machine shares system resources such as random access memory (RAM) , hard disk space, and the central processing unit (CPU) with the host computer. The major benefit to you is the ability to install operating systems in any order and without disk partitioning. You can minimize or expand the virtual PC window just like a program or folder, and switch between it and other windows on your desktop. You can install programs on the virtual machine, save files to it, and pause the virtual machine so that it stops using computer resources on the host computer.
You can download Virtual PC 2007 from the Microsoft Virtual PC 2007 website. Choose either the 32-bit or 64-bit version (for more information, see View your computer information), and follow the instructions on your screen to install the program.
After installation is complete, you'll create a virtual machine and a virtual disk for it to use. (Each virtual machine requires at least one virtual hard disk.) You can then install your additional operating system on the virtual machine. You'll need the installation disc or other installation media for the operating system and a valid product key.
If you no longer want the virtual machine on your computer, or want to reclaim the disk space used by the virtual hard disk, you can delete the virtual machine files in the My Virtual Machines folder, which is created in your Documents folder on the host computer when you install Virtual PC 2007. If you delete a virtual hard disk, any data stored on the virtual hard disk will also be deleted. Be sure to save any data that you want to keep to another location before you delete the virtual hard disk.
Click Start, click All Programs, and then click Microsoft Virtual PC.
In the New Virtual Machine Wizard, click Next.
Select Create a virtual machine, and then click Next.
Type a name for the virtual machine, and then click Next.
In the Operating system list, select the operating system you plan to install, and then click Next.
Click Using the recommended RAM, and then click Next.
Click A new virtual hard disk, and then click next.
Type a name for the new virtual hard disk, and then click Next.
Click Finish. The Virtual PC Console will display the virtual machine you just created.
In Virtual PC Console, click the virtual machine you want to install the operating system on, and then click Start.
Because no operating system is installed yet, you'll see the following message: Reboot and Select proper Boot device or Insert Boot Media in selected Boot device.
Ensure that the virtual machine window is the active window on your desktop, insert the installation disc for the operating system into the CD or DVD drive, and then press Enter.
The installation should begin within the virtual machine window. Follow the instructions that will appear to install the operating system.
To log in to the new virtual machine, click Action, click Ctrl+Alt+Del, type your user name and password, and then click Enter.
Now that the virtual machine is running your new operating system, you can install programs and create files, just as if it were a separate physical computer. For additional information on using Virtual PC 2007, open Virtual PC 2007, click Help and then click Virtual PC Help.
When you use a virtual machine, the mouse cursor will remain inside the virtual machine window. This can be confusing at first. To return control of the mouse back to the host computer, press the host key and then drag your mouse away. The default host key is the ALT key that is located to the right of the spacebar.