Which OS are you using?2000 and XP support up to 10 monitors!
Some motherboards automatically disable the onboard video chip if they detect an other graphics card, differs from board to board.
If you are in luck and your board does'nt disable its onboard video chip, there should be no problem for 2000/xp pro!
"The motherboard display adapter must always become the secondary adapter.
You must set up set up xp pro before installing another adapter. Xp pro setup disables the motherboard adapter if it detects another adapter. Some systems completely disable the onboard adapter on detecting an add-in adapter; if you're unable to override this detection in the BIOS, you cannot use the motherboard adapter with multiple displays."