Take it back out and see how it goes? If it works, go into the BIOS and make sure it is set to allow 'auto' or 'detect' graphics output method. It might still use the onboard output. You could try ...
I'm trying to get a COMPAQ Dual Channel Ultra2 LVD SCSI adapter with the SYMBIOS 53C896 chipset to work on my PC. I'm running a Tyan S1668 motherboard dual Ppro-200; with two Asus SC-875 SCSI UW cards ...