3rd monitor / second video card help

[Tk79]

(cross posted at CTH forum)
Please dont refer me to the FAQ because all it says is for a 3rd moniter you can just buy a 2nd PCI card. Here is my problem. I can enable either card (AGP or PCI) but not both. When I enable both my computer wont start up even. Is there a setting I need to change to use both video cards at once? Thx

[Orpheus]

We need more info. Some cards are incompatible, some mobos need a non-obvious change in the BIOS settings, etc.

[Tk79]

After much searching on the net I found that the first step to take is trying a different pci slot(dumbass). Fortunately that solved the problem because I have no idea what mobos or BIOS are. Thx though.