Well, if your sure that the hardware isn't faulty AND you reflash/restore your cfw....to no avail
Then it could only be one possible thing------You must accidentally and consistently flip the "HOLD" switch every time you go into the xmb. This happens to the best of us and we usually can't explain why or what provokes us to do it.... but, we can recognize the fact we do it and we must try to resist flipping the switch. Nah, just kidding!
If you do reflash/restore your cfw and it doesn't work then perhaps you aren't doing it correctly because that would almost definitely correct it (try switching to a later firmware perhaps)
-------if the above solutions don't work, I would have to say there is a hardware related problem (could be with the mobo, but am unsure)
GOOD LUCK!