I have read other related threads, but none quite seem like this. I upgrade to 12.04 today and every time I boot, the keyboard stops working. It works in grub and bios, but as soon as I am to the login screen, the keyboard looks like it isn't even running with the numlock key not lit up. The only way to fix this is to unplug and replug the keyboard. It is a USB keyboard, though I also have a separate USB mouse that works fine.