Radoeon HD 6770
i have an HP Media Center PCm7160n, running Windows 7 Ultimate SP1,
2.8 ghz, 4 gb of mem. I tried to put an Radeon HD 6770 video in it and the screen is black. The fan on my pc and video card are barely running. I upgraded power supply from 350 to 550. The card works in other computers. Onboard video is turned of. Currently there is an NVIDIA GeForce 9500 Gt that is running on my system. The computer repair shop said they had no clue, maybe the motherboard. They tried an 800w power supply and the same thing happened. Any clue what the problem could be?