Not to step on Broni's toes here...sorry Broni.
But you can upgrade from Windows XP to Windows 7, I have done it.
Here's where the problem lies however....the upgrade will work, but it will take your entire Windows XP WINDOWS folder and rename it WINDOWS.OLD, it will then create a new folder called Windows and install Windows 7 into it.
The only things that will remain intacted are any files or directories on C:
There is a program that you have to download from MS that transfers your system to a temp storage file, which depending on the XP hard drive size, the file can be quite large and require a lot of storage space.
Mine was 3 Gb. The transfer wizard as it is called, unzips the file and installs it into your Windows 7 directory.
How-ever you still have to re-install all of your programs again for them to work.
Edited by MrBruce1959, 12 July 2010 - 11:25 PM.