Popped in new PSU and HIS Radeon HD 4870.
750w, enough amps on the rail. Power supply is more than enough.
Computer is also fine. Phenom II 955 / 4GB 1066Mhz
When I plug my DVI into my card, it doesn't work, monitor doesn't get a reading, instant standby. Plug it into onboard, works just fine. Yes, I changed it in bios to use that card. Yes, I've tried resetting CMOS billions of times. Yes, it's plugged correctly in the socket and everything in hooked in properly. Yes, it's getting power because I was smart enough to stick my finger in the fan to check while it was running (ouch).
What is wrong with this video card?
EDIT: Also, yes, I've tried more than one monitor. I have it in a different rig right now with the same power supply which works fine with a 8800gt. Will post specs if really needed.
I think I understand you statement a little better.
Try puting the 8800GT into the computer that is having issues with the 4870.
There is a slight chance that the motherboard could have a faulty PCIe slot OR faulty chipset on the MB.
No, the 4870 works in neither. The 8800 does. It would be a faulty card if anything. It gets power and starts, but the monitor just always goes to standby. I just got on Windows7 this morning just to see if reformatting to a new OS would do something, now it doesn't even recognize the video card. The PCIe slot is fine, the 8800 works.