It might not be a power thing at all...my Windows machine used to restart randomly, plugged in or not, way before the problems with my power adaptor began. Then I found the little option under My Computer somewhere (Computer Information perhaps) that said "Automatically restart when Windows crashes" checked and I unchecked it. Now, instead of restarting, it goes to a blue screen of death, which usually informs me that Windows shut down to protect my computer and why. It often names the process at fault (ex: atapi.sys) and gives a long string of numbers like (00000x1...etc.). These things actually mean something, and if you write them down there's some help section on the Windows site where you can type them in and run a search and see if there's a fix for your problem. The error message will suggest things too. A surge protector ought to protect your computer, and if your unprotected things stay on when your computer restarts, it's more likely that it's a Windows crash. (If it's a home PC, it could be clogged with spyware) Good luck!