Need Help, 2003 H2

[ain731]

Hello, guys. I purchased my first Hummer H2 about 6 months ago and everything has been fine with it, last week as I was driving down the road the car just shut off and it doesn't even crank. I had the car towed to my house and started to trouble shoot what might have cause this. At the beginning I thought it could be the clifford alarm, but I disconnected the entire alarm system and went back to stock, but nothing. I went another way by bridging the starter relay with the ignition switch in running position and the car cranked but did not start, so the starter is fine but I kinda knew that since a busted starter would make the turn of once its running. I can hear the fuel pump and I dont think thats what it is because the car would crank if it was. The park/neutral switch? but again I don't think that would shut off the car while its running either. So I'm running out of my range of ideas. The lights on the dash light up, gages work, radio turns on etc. The car won't turn over or even try. It actually feels like if its a cut off switch, maybe factory anti-theft system? I had to buy a bypass module for my corvette when one day it wouldn't pass 2 miles an hour before turning off. But I doubt that's the case here. Please help me here, don't wanna spend an arm and a leg by taking it to a mechanic or a dealer. Any information is very appreciated. Thank you guys!