Possible Power supply problem

The computer is a P4,winxp,256 ram with a 300 watt ATX power supply.
I’ve been having trouble shutting down the computer through the normal shutdown process.
Now the computer shows no sign of power at all when I try to boot it up.. The processor fan and LED llights wont’t even come on.
Could this be a power supply problem or MB? Any help will be appreciated. Thanks.

Len Piko – okippiko@msn.com