My car will not start.?

I just bought a 2000 Hyundai Elantra and I think someone tried to put an alarm system in it because there are wires that I have to attach to start the car and detach to take the key out. Well I got up to go to work and my car will not start I checked the battery and it is good! The only thing I can think of is the automatic shut off happened with the alarm however I do not know how to disengage it. Can anyone help me PLEASE