GA-7DXR won't shut down/power off

Hi

My friends PC is based on a GA-7DXR mobo. He is running Win 98. Today
his PC fired up on its own and he wasn't in the room (he keeps the power
on at the case and the wall all the time). Now the PC wo't shut down. It
gets to the Win 98 is shutting down screen and sits. The fans are still
on to the CPU and in the power supply and the CD Drive light is
constantly on. When you switch off at the case then back on the PC boots
up no probs. If at the Win 98 shutdown screen you press and hold the
power switch to kil the power the PC boots up then shuts down but not
all the way. The POST screen displays then stops dead, however the power
to the cpu and PSU fans are still on, as is the CD drive.

I have changed the CMOS battery as I have heard this can cause freaky
power problems, but its still there. Before I start swapping out the
mobo and power supply does anyone have any ideas or experience with this
type of problem.

TYIA

hawklord_451