ok you may have a virus or malware
if you have no other option you might need to reset the computer back to factory defaults.
restart the computer and press Ctrl and F11 at the same time when the computer starts to boot this should bring up the pc restore tool. follow the directions on the screen and it will reset your computer.
The poster is trying to do a recovery !!! and there keyboard will not work when needed !
Im self taught ,and been fixing computer for about 10 yrs now,and im learning everyday so ,please tell me how a virus or malware is going to stop the keyboard from working when windows isn't even running .and don't say boot sector virus .