Alright, obviously you have driven the car utilizing this valet key, correct? You had to drive the car to the location where the repair work was done, or was it trucked in? My point is, if you've driven the car with said key then maybe the battery is run down? Just throwing out a few ideas. Or heed the advice given, take the VIN to GM, get a new PASS key III cut & maybe a remote to go with it.
I found the problem. It was at the engine bay'* fuse box. The day before I was looking for burnt fuses & when I opened the fuse box it had a plastic protector inside that had instructions to remove it. It was attached by 3 bolts... I started taking the bolts out when I realized that the plastic cover could come off without taking the bolts out. But I forgot to tighten the bolts again & as soon as I did the car started right away.
But thanks to all for the replies.