Friends 8800GTS problems

right first of my mate doesent have a clue about computers so im on a mission to find out a solution here.

I built the computer for him about 1 month ago and when he said his games run a bit sluggish i checked it out. First i opened up the computer and made sure everything was ok and i realised the card felt a bit toasty but the fan was connected. I switched it back on and downloaded VDO tool and Hmonitor and both of these programs showed up that the fan speed was at zero. So i updated the drivers and still no difference. I opened it back up again while it was on and the fan was spinning but at like 5RPM lol, so i took it out and tried it in my RIG and it worked fine, does this mean there is something wrong with his MOBO.

Ill have full specs of the pc tommorow but for now try and reply to the information ive kinda provided lol

yous rivatuner to up fan cycles.

Sounds like either his power supply is lacking sufficient output or maybe he did not connect the 6 pin PCI connector that it needs for juice.