I have a Dell Dimension 3000 computer, vintage 2004 / 2006. I need to know if this MB has a socket 478 or 775. It currently has a 2.8 GHz P4 Prescott processor on board. Replacement processors are available in either socket. Dell was unable, after 3 calls and 1.5 hours on hold, to tell me. If more info is needed, let me know.