This model doesn't have onboard video. Thanks anyway, though. I am in contact with Andy at Ultimarc and he mentioned somebody else had this problem with a Dell that was made around the same time as mine (circa 2003).
I'm just trying to list/eliminate possibilities. The card may simply be defective or (long shot), there may be an issue with the intel i875 chipset. I'm going to try this out using another computer tonight.