I'd first suspect a setting in the BIOS that's interpreting a "turn off" as power loss, and is trying to restart the system for you. This is usually an adjustable behavior via the BIOS setup: To access the setup tool, on many Gateways, you tap the F1 or F2 key about once a second or so as the PC wakes up from a cold start. (Other brands and models use the Del or Esc or other keys. Check your owner's manual, or the online manual at the vendor's site, for the exact method of accessing the BIOS setup.) Once you see the BIOS setup screens, look for something relating to "restart after power loss" or "system state after AC back" or any similar concept: The idea is to find a setting relating to what the PC does when the power goes out. You may find this under "Power Management" or some other section of the setup pages. Once you've found the setting, adjust it so that the PC stays off after a power loss, instead of "turning on," "waking up," "reverting to previous state," or whatever other verbiage you may see: You want the PC to ignore a power loss (for any reason, including a "turn off" event) and simply stay off. If the above turns out not to be the problem, then the BIOS or power supply may have problems. (It's also possible it's a software issue in Windows own power management routines, but that seems very unlikely.) You might try re-flashing (a kind of upgrading) your BIOS, via the info and instructions on the vendor site (search for "flash" and "bios"). Other vendors sell replacement BIOSes too, if you'd rather go that route: http://www.google.com/search?q=replacement+bios If that doesn't help, I'd suspect the power supply. You may also wish to see if your vendor offers replacement power supplies; or, try an aftermarket source. Power supplies don't have to cost a lot, and they're surprisingly easy to replace (usually just four screws!): http://www.google.com/search?q=replacement+power+supply