So, I recently tried to start up an old computer of mine. It would not power on, so I replaced the PSU. When I powered it on, all the fans spun up and the POST beeps indicated a normal startup. The problem was there was no video output. Every couple of minutes, I hear the post code again. I think it is restarting after POST, but without video I have no idea why. Does anyone have an idea as to why this is happening, and how to fix it?

EDIT: The video card is a PCI-e card. There is no integrated graphics on the motherboard. If I remove the video card, the POST indicates a missing card. When I put it back, it goes back to normal, so I know that it recognizes that the card exists.