Video Card IRQ Interuption Problem

Try moving the modem board to another slot. Also, try changing the BIOS setting for "plug and play OS" to see if this gives you the ability to change the IRQ under windows. Be sure to tell the BIOS to "clear configuration on next boot" after moving a board, otherwise it stupidly keeps reserving resources for the board in the old slot. Check your motherboard manual (or at the manufacturer's web site) to see if it tells you how the PCI slots are wired to hardware intererrupts. What happens is that some slots share a low-level hardware interrupt and usually at the software level they will end up sharing an IRQ, too.