I have a Sony Vaio Windows XP with Radeon 9200 graphics card which came with it stock. I just bought a Radeon 9550 and installed it. When I turned the computer on the moniter says no connection/power and just stays black, I read up on this and have put the old graphics card back it, and went to device manager and then driver display then unistalled it . Took it out the old graphics card again and put the new one in but still no luck. Can someone tell me what i'm doing wrong?