'amazed',
Hi & Welcome to Windows 7 Forums
I have both Windows 7 x86 & x64 (2 different platforms) in the same computer, dual-boot. (Never mind it's actually triple-boot cus it has Vista in it, also). This is doable because both 7s cannot run simultaneously AND they are not the same OS (1 is x86, the other x64) nor were installed from the same disc.
I trust you see the point & why you are hitting a brick wall.
Cheers,
Drew
"A scan a day keeps the nasties away!"