Chevy Cobalt wont start, engine is "locked"?

[Ruby]

My 2008 Cobalt won't start. When I turn the key they smybol on the dash that looks like an engine with a lock on it lights up. I've checked the battery and fuses which all appear to be fine. The car seems to be in security lockdown. I haven't made any changes to the wiring or anything so I don't know what caused this.

I'd like to fix this myself if possible. Any ideas are appreciated!