Was the card used? that would most likely be the problem.
1. Try the card on another computer and see if that works.
2. Try another card on your computer and see if it works.
If the card does not work with the other computer, then it's a problem with the card.
If the card does work with the other computer, it may be your motherboard/etc that's the problem.
There's a trick to fix an 8800 GT with an oven, as the artifacting (colored dots) may be caused by bad soldering/ connections.http://www.youtube.com/watch?v=T7um_hZYom4
^^^Video on how to do it^^^
if you need written instructions, just google "8800 GT oven trick."
QUICK EDIT: you might not have to replace the thermal pads.