I installed Bootcamp and then Windows 7 x64 sp 1 on a new iMac 27 with 3 TB fusion and OS 10.8.3. The Windows 7 install went smoothly, i then ran the apple bootcamp installer, and that seem to go OK, but when the system restarted and the windows 7 start screen with the password came up, the mouse light was off, and the keyboard won't work. Tried 2 different keyboards and mice. Rebooting to OS 10 and the keyboard and mice work fine. I can't enter the password on the Windows 7 start up screen 'cause the keyboard and mouse aren't seen. Before I have to do a complete reinstall, anyone have any ideas???? Other people having the same problem http://forums.macrumors.com/showthread.php?t=1509773 It is a bad USB 3 driver that has to be replaced.