Originally posted by stevenrodz
so i need a whole new mobo?
If your mobo doesn't support AGP then I suggest it might be time to upgrade but there are still PCI cards out there like ATI 9200 PCI which is MUCH better than Intel Extreme. PCI cards are garbage but if you're happy with it then you're happy.
When you install the new videocard you must disable the onboard. You can go into the BIOS to do that. The videocard you have is integrated into the mobo but that does not mean you have to replace the entire mobo to use a new card.
I'm pretty sure your mobo does not support PCI-E so DON'T mistake PCI for PCI-E. They are two completely different things.
As far as Dell compatibility I couldn't tell you because I would never buy a Dell but the other poster is right. Dell likes to configure things to their own liking and their cases are not upgrade friendly.