I have a radeon ATI hd 5770 that was working just fine.. The computer wasn't working so I took it off for a few months until I got a new motherboard and processor.. Now it doesn't work at all but the built in card is working so it's not the monitor.. When I turn the PC on I get a black screen even though the fan on the card itself is working.. I'm certain it's compatible with the rig I have and I've paid a lot for it so what could be the problem?

How is the bios set? Did you install the correct drivers... and did they give any errors during the install?

How is the bios set? Did you install the correct drivers...and did they give any errors during the install?

I set bios to make PCI first choice.. Since then I can't even access BIOS settings or access windows.. I don't get signal using the pci card.. And when using the on-board graphics I only get the first screen with the GIGABYTE logo and then all black. It

You will be able if you rest bios... take the button cell battery off the motherboard... Usually it's a CR2032 or a similar number. Take a pair of tweezers and short out the pins that touched the center ob the batter and the edge. ( Of course with the computer unplugged)

DO that for a minute or two... then put the battery back in, plug the computer back in... move the monitor back to the built in card and it should work there again.