A couple of questions for clarification:
1. Does the keyboard function for you to edit the BIOS settings? (just to check and see that it is not a keyboard hardware problem)
2. Does ctrl+alt+F1 bring you to a terminal prompt? If so, does the keyboard work there? (just to check and see if it is an xorg configuration issue)
3. Is it a USB keyboard? If so, do other USB devices (like perhaps your mouse) work?
4. If you have a live CD, you can boot into it and make changes to the files on the hard disk. Do a search on rescues using Knoppix. If it is an xorg configuration issue, you would need to edit the file in /etc/X11/xorg.conf If you have a working configuration file on the live CD, you can overwrite the one on the hard drive with it.