2008 chevy cobalt wont start

car clicks when I turn the key , all lights and electrical come on but the engine will not turn over

When you do try to start, do the lights go off?
Check the battery connection, especially the fat one going to the starter.
Get a short piece of wood, place one end on the starter. Hit the other end of it with a hammer.
See if it wants to start.

We had a similar situation a couple of weeks ago. The battery was dead. If the remedy RemcoW suggested down’t work, take the battery to an auto parts store. The will test the battery for you. I need to replace my batteries about every 4 years; maybe you do too.