Contact a local dealer or if you have Onstar call them.

I ended up having it towed to the dealership.

Did the battery go dead or get low for any period of time first?  Have a friend with a Cobalt that did the same thing.  Turns out the dead old battery tripped the anti theft system.  Basically that cut power to the ECM until a sequence of steps was done to clear it.  Anything like the windows and seat worked.  Anything needed to drive the car was dead.  

Turned out it was fuse.  An expensive one, $109!!!! That's just the fuse!  Somehow I must have shorted it out when i changed the battery.

Hi Ken

Count yourself very lucky if that's all you fried.  🙂

I replaced a computer in my 2001 in 2005.... $4, 900 dollars.... you were lucky!!!

Had a no start again last week.  I was moving cars around and on the third start, pushed the start button and everything went black, worse than the first time.  Had it towed to the dealer again and I told them there was something else causing the problem.  They found the hot wire from the battery to the starter was loose at the starter.  Tightened it up and all is good.  They think this may have been the problem in the first place.  Anyway, fixed for no charge.