r1y23 said:oh crap, one pin is missing, oh well quick fix
If you are talking about the pin header for the power button/LED, the missing pin might be normal. Check the pin block, it should be solid where that pin is missing. As for the computer still not starting does it have diagnostic lights on the rear? Most desktop Dells have a A-B-C-D led readout giving diagnostic status readouts. Dell.com openly tells you the codes...good luck.