HD4870; computer won't boot when its installed.

[SlickAlpha1]

I've got the sapphire hd4870 512mb which i bought in sept '08.

The other week i was playing gta4 and my computer just switched off and refused to power up again at all.

I RMA'd the PSU to Ebuyer who tested it, found it to be faulty, and issued a replacement under warranty, but even with this fitted the machine would still not start.

I have found however after a bit of trial and error, that if i take the video card out and switch on the power, the comp will start up, but after re-installing the card the computer, as before, will not even power on.

Any ideas on this?

 

[mactronix]

What power supply is it ?

Mactronix

 

[SlickAlpha1]

Its OCZ StealthXtream 600W

I tried an older graphics card in today and it powers up with that in but there is no video output and the comp does not seem to boot at all; just sits there and hum.

 

[dzgx216]

Its OCZ StealthXtream 600W

I tried an older graphics card in today and it powers up with that in but there is no video output and the comp does not seem to boot at all; just sits there and hum.

Sounds like it could be your PCI express slot on your Mobo. If you have an old PCI video card laying around anywhere, try it in one of the regular PCI slots on your motherboard. Not that it's likely that many people have such ancient objects at their disposal anymore considering we went to AGP after PCI and that was quite some time ago.