I just bought this card recently and it didn't power up. My old card "fried" but it still powers up. So after that I RMA'd my Motherboard and got it back today..Problem is the card still doesn't power up. So for good measure I plugged in my old card and it powered up but still had no display. I'm annoyed because I can't afford to do all kinds of work to it.
Here's my specs
Intel Quad Core Phenom 3.2Ghz
8 Gig RAM
Sapphire HD 7770
My old card is an EVGA GeForce GTS450
My New card is a Sapphire HD7770
Make and model of power supply + amps on the 12v rail.
Did you connect the 6pin power connector to the card?
Try installing it into the other pcie slot, does it turn on?