Before you buy
Make sure your PC is compatible with Windows 7. Download and run the
Windows 7 Upgrade Advisor.Running Windows Vista?If you have certain versions of Windows Vista, you can purchase Windows 7 Upgrade versions. You can do a clean install (back up your files, clean install, and reinstall your applications) or an in-place upgrade (Windows 7 installs over Windows Vista).
Running earlier versions?If you have Windows XP or a version of Windows Vista that cannot be upgraded to the version of Windows 7 that you want to install, you can purchase Windows 7 Upgrade versions. But you must back up your files, clean install, and reinstall your applications
If you’re running Windows 2000, a different operating system or have a computer that currently has no operating system, you’ll need to purchase the full product and do a clean install.