ignition key will not turn on 1994 Ford Tempo

ignition key will not turn. key goes in but will not turn. Steering wheel does not appear to be locked to the side. Sometimes it will start working, but now it will not turn.

2 answers
replace lock cylinder try to get it to turn to the on position one more time and if you get it to turn use small drill bit to push in small brass lock nipple on lock cylinder and pull key at the same time if key jus wont work you will have to drill out brass nipple
It's your key cylinder. Youcan purchase one at most auto parts stores. Also, your key may be worn to a point that the cylinder will not accept the key any longer. If you have a spare try that one.