Check to make sure drivers are installed on the new card and if that doesn't work I would just buy the number of video cards for the number of monitors you need then plug them up. two PCI Express 2.0 x 16 cards and PCI card (lower quality though) just make sure you computer can handle the power requirements and if it doesn't i would also buy a new power supply with higher wattage. If you have a DVI to VGA adapter use it on the current graphics card then to the monitor. This is what currently come to mind.
