I am unable to shutdown the pc. It keeps automatically restarting soon after the display "windows is now shutting down". I resort to switching off the power. No problem restarting when I switch power back on. I have windows 98SE. Thers has been no similar problem last 3 yrs. Have not added any new hardware or software recently. I am loathe to reformatt the hard -drive. Anyone got any suggestions. Thank you.