I have a multi-boot Raid 0 system that has XP x86, Win 7 x86 RTM and Win 7 x64 RC.
I tried several times to replace a Win 7 x64 RC install on a partition that of course had expired, but it won't finish the install and gives a message something to the effect of unable to install the selected language, and I know that I have selected English etc.
I also noticed that the small system partition is 200MB so I must have installed an earlier version of Win 7 and then the released candidate first and then XP as some test at the time
ASUS Maximus V Gene MB
Windows 8 X64; Windows 7 X64; Windows 7 X86
16GB Corsair Vengeance Ram
eVGA GeForce GTX 550 TI
Corsair GS700 PS
1TB Seagate SATA 6.0Gb HD