Just bought the car. Drove it a few hours and stopped for lunch and it won't lock
I open the doors and it beeps like I left the keys on, I lock the doors on the door panel with th switch and they unlock.... help.

 

put the key in the ignition and push the small button behind the key

 

I am not stupid, I already tried that....

 

There is a sensor (switch) built into the ignition key cylinder that detects the key being inserted. If this has shorted in a closed position, this could be your problem. To check this, take off the steering column covers that are around the ignition switch. There are 2 wies coming out the bottom of the key cylinger. Follow these wires back to its connector and unplug them. Then see if you still have the problem. If you want, check the wires coming out of the cylinder for continuity. Open connection is when the key is removed, short is when the key is inserted.