Car won't start!!!!

Theres a 95 G20 at a salvage yard that won't start. it has never been in an accident. Tried jump starting it, it cranks but won't turn over. i think its getting gas because the car has half a tank of gas and when you crank it, you can smell gas in the engine bay. Now when u try to jump start it, the security light comes on and while cranking, it stays on, and i can't find a switch to deactivate it. can anyone tell where i might be able to find a switch, or how i can get that puppy started because they're only asking $2000 for it, and its a 5speed . thanx