Hmm. It might be your start-up items. Disable them all (Start -> Run-> type"msconfig" ->Startup -> uncheck all the items) and see if it works. If it does, then enable all that were enabled before and slowly weed through the ones you dont need (google entries if you don't know what they are).
Also, I got a slight delay (of maybe a second) at that time when I upgraded my video drivers. Have you done anything of that sort recently? Even if you haven't, it might be worth a shot to reinstall them.
AGP won\'t fit in PCI-E... unless you use a really good hammer. ~Trotter