I've just upgraded to Windows 7 x64. I've managed to change my 'Program files' DIR from C:\ to E:\, but not the 'Program files x86 folder. I don't know if this is because I already have stuff installed in it or something? ie. I've installed stuff into the x86 folder before changing the path in the registry and restarting.

 

I've changed the locations by editing the registry at

 

HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows > CurrentVersion

 

Here's what it looks like. These haven't been changed since restart.

 

I'm pretty sure you can't do that because there are made registry entries which leads to the the C:/ path, and if you move your applications they will simply not work. However it is possible to reinstall them on the D:/ drive.