PC runs XP MCE.

2 scenarios

1) PC is on and running. I walk away for a while or whatever and when I come back the screen won't wake back up.

2) PC is running with power cord plugged in. I unplug and screen goes black and won't respond/wake up.

In both scenarios the PC stays on and I am forced to shut down by pressing and holding the power button which I know is generally a no-no.

lastly this doesn't happen all the time. Sometimes I walk away come back and teh monitor responds fine and sometimes I unplug the power cord from the back of the laptop and monitor stays on just fine.

Thanks for any help