Issue with graphics card. ATI 6870

[Meresgi]

So i've run into an issue recently. I have 2 crossfired 6870's made by XFX, they were working just fine but when the latest Blizzard patch hit, it apparently coincided with my cards going all fucked up. I'm pretty sure it's the cards as I only notice lag with WoW open, where you can hit the character tab and not see any of my armor icons loading up correctly.

I've tried to reinstall the drivers for my card, but here is where I have run into a snag. Each time I download the latest drivers from the ATI site and run the installer, at the end it tells me that it has failed to install the display driver. (I've tried 5 times, each time it's a Fail).

operating system is Win7 64bit and downloading the correct drivers. The cards are not overheating when I monitor them. Kind of at a loss as to what to do now. Perhaps I could pull out the cards and swap their places?

[Sonomaa]

pull one, run a test, see if it works, swap them, could be that one of them went bad
an old video card I had failed to detect by the manuf drivers, which usually signals the card is going fubar, with two of them you have a chance its only 1 of them being fubar

[Niya]

Have you tried to uninstall the current driver completely, reboot, check via device manager that it's really gone (or if not, remove it there too), reboot again and then try to install it again? Installer failing really sounds like something is screwed up with the driver...

[Meresgi]

Have you tried to uninstall the current driver completely, reboot, check via device manager that it's really gone (or if not, remove it there too), reboot again and then try to install it again? Installer failing really sounds like something is screwed up with the driver...

Yeah I did this last night

I'll pull one and check them tomorrow when I get back from class. Right now it seems for w/e reason to have stabilized itself and i'm not getting any terrible issues. I hope one hasn't gone belly up yet, bought these damn things back in May.

[xerodok]

What kind of power supply do you have? If you have one with removable cords, make sure that they are seated all the way. If they are, try alternate ports in the power supply, one could have shorted or gone bad. Very unlikely, but the supply cords could be damaged too (if you cable organized hardcore and bent them the wrong way, etc)

Try what Sonomaa recommended first, though.