I installed Windows 7-64 bit on an iMac (27" late 2012). Mouse and Keyboard worked during the installation process. But now when I'll try to log in into windows, I am stuck on the login screen because my USB keyboard and mouse aren't working. It looked like during the windows installation process that my mac installed the bootcamp drivers correctly (Version 5.1.5621).
I tried to reinsert the USB mouse/keyboard. Boot without and then insert. Switch the USB ports etc. Any idea how to fix this?