Pontiac Repair: 2007 stalls, fuel pump, seatbelt

Question
I have a 2007 grand prix with only 52,000 kms on it.  Bought it in August, car worked perfect till the other day.  I went to leave work, started my car and went to put my seatbelt on when it stalled.  This happened 3 times, when I went to move it, it did the same thing, after that it would crank no problem at all but wouldn't start.  Had it towed and ready to go to the dealers after sitting for a week.  My brother left the key on for about 45 mins while putting it on the trailer.  The car started again and ran for two days, this morning was fine until I started down the road and then it died on my while going down the hill, got it started a few times, stalled a few times, manage to get it to a garage close by and seemed to be fine after that, do you have any idea what this could possibly be, some are saying anti theft, others saying battery.  Can you please throw your suggestions my way.  Thank you, Sue.

Answer
Hi Sue:

Well first off this car is still under warranty so you will not have to pay to get it fixed. I don't think it's battery or anti theft related. Anti-theft will not allow it to start and run. It will not make it stall going down the road. If it were a battery issue you would have a lot of ther stuff on the car not workin or working right, the clock would reset on the radio etc.... It could be something like a fuel pump issue where it doesn't have enough pressure to run the car. or it could be a spark issue. If the car hasn'r set any codes in any of the modules it will make it hard to pinpoint the problem. My guess it there is some codes that have set wich will allow the dealer to trace the issue back to something common Like what I mentioned. Good luck :)