Which version of Windows 7 on Bootcamp?
Which version of Wndows 7 can I install via Bootcamp?
iMac, Mac OS 8.6 or Earlier, 21"/8 RAM
You can install Windows 7 Home Premium, Professional or Ultimate, and you can install a 32 or 64-bit version depending on your iMac. See > http://support.apple.com/kb/HT5634