PCI express 2.0 x16 clashing with PCI

I just recently put a 9400gt pci video card in my comp to run 3 monitors, it is running along side my 9800gt pci express card.

I have only 1 set of drivers installed for the both of them, the 191.07 nvidia drivers(latest for windows 7 64bit) non beta drivers.

My question is, before I ship this back to the company I bought it from. Is this a hardware issue, or a software / driver issue? Do I need to install drivers for the 9400gt separately? If so plz direct me on doing so if possible.

the monitor seems to respond like the video card is acting with no drivers, aka choppy window dragging etc. So I figured i'd ask before I rushed into shipping it back.

If anything else..I'll just replace the mobo with a sli compatilble one and buy a cheap 9800gt..but I just wanted this third monitor to throw apps on, the other two are on the pci express card for gaming/hd movies.

Help is greatly appreciated.

I'm at a fairly high understanding of hardware and software alike. I've tried most to everything I could think of, but this is the first time I've delt with using PCI express and PCI together.

amd phenom x4 9950 be am2+ 940
gigabyte ga-ma770-ud3 rev 1.0
4gb 1066 ddr2 g.skill
evga 9800gt pci express
sparkle 9400gt pci
160 wd black
750 wd green

Tried that. Still get the same freezes.

Thx for the quick replies, but this thing is just owning my setup..pretty sure its a dead card. I can't even drag a winrar extraction window, or copy data window to that monitor without getting a freeze and having to hard boot.

Ordered another pci video card a 6200fx nvidia card..hopefully that does me better.