car wont start

what kind of car?

(year make model)

I just had an o2 Intrepid in my shop, and checked the battery and the starter with no success.

wound up being one of the computers, and very expensive.

Are you testing for power, or just replacing parts?

I suspect it's a problem with the hebridizer and its connection to the thermilgator. If you already ionized the gonklar valve then apply more pressure to the federline hose. If all else fails, call a mechanic.

Could be:

Fuse - either a main fuse or starter signal
Starter relay
Loose or cut starter signal or power wire
Bad or unplugged ignition switch

To diagnose you will need a test light or multimeter. You want to test for power at the start for the large power wire connection. Next unplug the starter signal wire at the starter and with someone turning the key, check for power. If both those check out, you still have a bad starter. If not signal, its a bad fuse, relay or switch. Check all your related fuses to eliminate things one by one.