Problem first started with the USB inputs being unrecognized. No mouse, then no flash drives, etc.. Progressed to no video. A chat session with HP resulted in a dead mb diagnosis. Ordered a refurb from Express Technology in AZ, and it came today. Both boards are stamped exactly the same, Rev. # and everything.
Did the swap, and everything was uneventful. Had the memory in the wrong slots, so nothing happened at startup except repeated beeping. Changed the slots in which the memory was installed, and the beeps stopped, and the blue screen with access to the boot menu, the setup menu, and the system recovery menu comes up, but everything locks up there. You can hold down escape, or F10 at power up, and the screen will say "loading boot menu", or "entering setup", but neither actually ever happens. Nothing at all happens when you hold down F11 for system recovery at power up.
If anyone has any suggestions, it would be immensely appreciated!