I've had PS/2 keyboard problems in F17. Two things to try:
1. Hold down a key and see if it starts auto-repeating. In my case, the
first keypress is lost, but auto-repeat keypresses get through.
2. Ctrl-Alt-2 to a text terminal and see if the keyboard works outside
of X. In my case, it did.
If your keyboard problems act like mine, you have the same problem, and
it's a bug in the X PS/2 keyboard driver. Killing X resets it, and a
USB keyboard seems to work fine.