Strange Monitor Problem - maybe

I just finished setting up and installing programs in a new PC running

windows XP.

Something must have happened and the monitor screen went black. If I

try to hit "reset" I can nothing seems to happen. I think the computer

shuts down and restarts but the screen remains black

The only way I can get the monitor to work (if it is the monitor) is

to unplug the PC (when the screen is blank) and plug it back in. Once

I have a screen and shut down normally using the start menu, the next

time I try to start it up I get nothing but a black screen. I can't

even tell if the PC is booting up or getting past the cmos boot up as

the screen is black. I have tried a different monitor and the same

thing happens so i know it's not the monitor. I'm lost as to where to

go at this pint. Has anyone run into a problem like this/ Any ideas

what could cause this to happen? A driver or something?

Please help

Thanks

Miike