The computer is a HP Pavillion 'a220n.' It has Win XP home, 512mb ram, Athlon XP 2600. It had a GeForce-4 video card that was replaced under warranty about 5 months ago. I forget what they replaced it with but it was not an Nvidia geforce card, it was from another company. All of the sudden the screen will turn black like it went into sleep mode, and I can't get it to turn on by moving the mouse or by clicing the keyboard. The computer itself is on during this, bujt I haved to turn it off and on again to get the monitor back on. This happens randomly, someimes when surfing the web or using the computer to do homework, but my kids play video games when it happens most. What do you gus think I should look at or try? Thanks in advance, I'm off to work and will check back this eve.