Windows 7 Upgrade chart

If you are looking for upgrading to Windows 7 from your current system which could be XP or Vista, Walt Mossberg @ MossBlog, has come up with an exclusive chart which can clearly tell you that you can upgrade ( in Place ) keeping your system intact or you need a custom install to another drive or format everything to get a fresh start.

Windows upgrade chart

Windows 7 upgrade chart ( Click to Enlarge )

Also you can check out Windows 7 Upgrade Advisor along with video on upgrading to XP