my computer keeps powering off...sort of. I run Win XP home on my desktop. When i turn it on and log in, i have about 1 minute to get situated before the screen goes black and i get the "monitor self test" message box that says the monitor is working fine. The thing is, the green power light on the box is still lit. I have to hold down the power button for a few seconds to get it to completely power off, and then i turn it on, log in, and go thru the exact same thing again...every time. any thoughts? oh, and i got the computer in feb of 2004, and it's a gateway, if that makes any difference.