No Video on PowerupFollow

So I finally got in all the parts for my new computer. The graphics card came a little late, so I used an old one I found in an old computer temporarily. (Mobo doesn't have any on-board video, MSI 790X-G45) It worked fine, booted, installed Windows 7, and all that stuff.

But then my new graphics card came in today, a Sapphire Radeon HD 5830. I took the old video card out, put in the new one, got everything hooked up properly and turned the computer on.

Waited a bit.

No video whatsoever. The fan on the card turns, so I know it's at least getting power. So I fiddle with it for a few minutes, reseat the card, check my cables and try again.

Nothin'.

So I put the old card back in (I don't take the new one out), plug my DVI cable into it and start up just fine. Any ideas on why I can't get any picture with the new one?

For the drivers, use the latest and greatest catylist drivers from AMD / ATI whatever they re calling themselves these days