Originally posted by condor:
I, on the other hand, will try something different first (before re-soldering a mobo )


Agreed! Especially if MoBo is covered by
warrantee.


disconnect the cable from your Power switch to the motherboard - it might be shorted ...

seen that before..
I've seen it also...

You can check Sowulo's suggestion - reset to default or simply change BIOS settings and see, may be it help You to solve Your problem. Resoldering is always last option. Good luck!