Hmm, if he flashed it wrong it may be a problem, do you know if he really flashed the CMOS? If not then just clear the CMOS using the clear CMOS jumper next to the battery on the motherboard, it consist of 3 pins and has the jumper normally across 1-2, set it accross 2-3 then power on the pc and it should go straight to the BIOS and you can set it to factory defaults and then shutdown, put the jumper back across 1-2 and it should work.