I got my new graphics card for Christmas (XFX Radeon HD 6750) It needed a at least a 450w PSU. So today I went out to the store and bought a nice Antec 500w.
I removed the old one and screwed in the new one and plugged everything in and added my graphics card and connected it with the 6-pin cable from the new PSU. Then I connected the moniter with the DVI cable, then I started the computer and it turned on but no image went on the screen and everything was running, the motherboard light went on, DVD drives worked, and the fan on the graphics card that I installed works. The old graphic card doesn't even work now. Then i tried HDMI on my TV, still nothing. What am I doing wrong?