The problem is you bought your rig from dell.... if you have a digital camera take some pictures and post them.... If i am thinking right a PCI-E cards little copper interface chips on the card that you push into the slot should be a short little of half and inch, then a long one for the rest of the slot, PCI would have the long piece then the short one should be backwards from PCI-E, then an AGP slot on the mother board would really be offset to the right compared to the PCI slots below or above it. The cards interface pieces usually are divided into 3 pieces but there are ones are just 2, the long piece is usually short than the PCI ones hence the shorter piece is typically longer than PCI. Hopefully this makes sense if it don't ignore me. Or just post a pic of your mobo and card.
(bah you i figured it out before i typed it)
(bah you i figured it out before i typed it)