PC not shutting down(really, no noob prob)

[Neotheone]

well i have a milti boot (win98+winxp prosp2) system, my UPS was not working so i left it @ home and my sis ran the pc without it, for some reason,
after i came back, the system wont shut down in 98 or in xp . the processor fan keeps running and the HDD seems 2 make a noise. although the monitor is
blank. when i restart by switching the power off and on, it restarts normally.
could u tell me where the problem might lie ??

IS it the SMPS or the Motherboard ???

help !!

 

[Renegade]

I had similar probs once but that was bcoz of some virus.
You may not like my suggestion but I would have formatted my HDD and reinstalled everything.

Another thing could be that there is some prob with the ATX config but then it would at least show 'its now safe to turn off your PC'.