Radeon 7770 Compatiblity with Dell Inc. 0G3HR7

Hey there everyone.

Long story short, ever since i upgraded my video card from a Radeon 5770 to a 7770, my computer has been completely locking up and crashing at random times. I put my old card back in, so this seems to have solved the issue. My major concern now is if its most likely that the card itself is just bad and i can easily replace it, or if its a bigger problem with my Dell motherboard (Dell Inc. 0G3HR7) not being compatible with the card. Ive looked all over the web for a simple answer but cant find one. Help would be nice.

Thanks!