I have a 2007 Chevy Cobalt that won't start. It has power but won't turn over. I can hear the starter click, then it just loses all power. I tried to jump the car, but it still won't start. I assumed it was from a frozen line, because my car was empty the last time i drove it, and it got to minus 15 below zero. But after a few days of warmer weather, still nothing :(

SOURCE: chevy tahoe won't turnover, power

Next time it won't start turn headlights on and see if they dim when you turn key to start, if they dim its most likely starter, if they don't dim possible starter switch, Have you tried to start it in neutral position? Try that, if it starts in neutral than its park neutral switch, if not could be starter switch, Just make sure you chk. all fuses and any relays associated with ignition first.

SOURCE: chevy 1997 3500 vortec won''t crank in cold

CHECK BATTERY WITH A LOAD TESTER,CHECK CABLE CONNECTIONS,AN STARTER . TRY JUMPING WITH A BOOSTER PAK THAT SHOULD START IT IF NOT REPLACE STARTER.

SOURCE: 2007 chevy cobalt ls won't

Ignition relay or fuse could be the problem. When you turn the key to start do you hear a fuel pump kicking on and or do you have spark when you hot wire the starter (I know it's hard to check while trying to start it)? You can email me back and I might be able to pinpoint it more.