Help installing two video cards?

I am wondering if I can install two video cards on my system. I have an Asrock 775 Dual-VSTA mother board that has AGP and PCI-E slots. I have a BFG 7600GT that I bought and I am running right now, however I want to put my old ATI 8500 AiW back in to run just the TV. I put them both in and the machine runs fine, but when I try to install drivers for the ATI it either says I can't or hard reboots every time. Tried many drivers for the card old and new. Is there an order I must do this in or something. Thanks in advance.

Somebody will know if it's possible, I have heard you can't mix ATI/Nvidia drivers but it's possible someone has hacked drivers that may do the trick. Give it some time, forumites come out around this time usually

Have you tried pulled your PCIE card out and installing the 8500aiw drivers and makeing sure it boots up then reinstalling your PCIE card?

Might be worth a shot. At least that is what I would try if it was me that is.
Good Luck