Desktop power up issue

Hi

I shut my desktop down and when I restarted it the next morning the power indicator lights came on and I could hear it running but nothing appears on the monitor. I checked to make sure that the monitor cable was properly attached and not loose. That wasnt the problem. Also I can't turn off the PC. I had to turn it off by pulling the plug and the strangest thing was that once I re-attached the plug the PC switched on without me having to turn it on manually (which is usually the case)


Any suggestions on how to sort this out?


PC is running WinXP and is a p4 240ghz

Thanks in advance