Know what will work before you upgrade

Requires a clean install. Back up your files, install Windows 7, then reinstall your applications.

In-place upgrade installs a new version of Windows over an existing edition.

Your Windows Operating System and Edition	Windows 7 Home Premium	Windows 7 Professional	Windows 7 Ultimate
Windows 7 R.C. or Beta Operating System
Re-install Vista or XP to be eligible to use Upgrade	Full	Full	Full
Windows Vista Operating System
Windows Vista Home Basic	Upgrade	Upgrade	Upgrade
Windows Vista Home Premium	Upgrade	Upgrade	Upgrade
Windows Vista Business	Upgrade	Upgrade	Upgrade
Windows Vista Ultimate	Upgrade	Upgrade	Upgrade
Windows XP Operating System
Windows XP Operating System	Upgrade	Upgrade	Upgrade
Older Operating Systems (Editions not included)
Windows 2000	Full	Full	Full
Windows ME, 98, 95	Full	Full	Full
No operating system installed	Full	Full	Full

If you have a 64-bit machine:
If you are running a 32-bit OS and want to upgrade to 64-bit, you must do a clean install with bootable media, such as a CD, DVD, or USB flash drive.

If you are running a 64-bit OS and want to change to 32-bit, you must do a clean install but don’t need bootable media.