SS51G Overheating and won't wakeup

I am having a problem for a few days wih my SS51G. The fan is runnig
on hi and the unit appears warmer than usual. The problem I am having
is that if the system is siting for a long period of time, The fan is
still running and it will not respond to mouse or keyboard. Num Lock
LED for example does not go on or off when this happens after I reboot
it everythign is fine. Another interesting clue is that he turning the
mouse wheel makes the fan go slower!! Any body have seen this sor of
this? Is this a problem with BIOS or OS?

Thanks