I recently built a computer with Gigabyte UD3, Intel i7, OCZ ModXstream Pro 700W, and Sapphire HD4870 1GB (if you need other specs, let me know). When everything except the Sapphire is connected, everything boots fine (but I cannot see anything, obviously). When I connect the graphics card, it boots for about 10 seconds, then turns off. A few seconds later, it boots back up and then turns off at the exact same point (over and over again). The point it turns off is within a second of showing the first screen, which tells you which keys to hit for BIOS. I tried a new power supply and a new card (same models, thought they might be defective). Any idea what could be causing this?
Yes, I'm using the PCIe connectors on the card. If I don't connect them or only connect one, it says "One of your power cords is not connected to the video card." Everything else boots fine, and it stays on. It most likely gets to the part that tells me I do not have a boot disk, since there is no operating system, but I can't see it. Since everything else boots, do you think it would be the card that has a short? I got a replacement card, and it does the exact same thing.
I just read the checklist in the other post, and I've verified all of thos except the CMOS. I will look into that when I get home tonight, I'm currently at work.