so when you say it won't start you mean the key does not want to turn ? is the steering wheel locked ? if the key always turns and if you wiggel it and to does turn and start, it is the key or the Ing. switch. try a few different keys. the switch could be warn out, what is your year ?

2001 5sp. K&N stock filter 215/70/15
If your check engine light is on at least you know the light still works