I have an HP Probook 6455b. I bought it secondhand, as poor people are wont to do, and it came to me nearly fully functional, save that the battery won't hold even a moment's worth of charge.
As long as it stays plugged in, it has served me faithfully for several months now. I think it's running a legally registered and purchased build of Windows 7 Professional x64, with Service Pack 1. CPU is an AMD Phenom II Dual-Core. It has 4.0GB of RAM, and the video card is an ATI Mobility Radeon HD 4200.
It keeps turning off. Not shutting down; Whilst plugged in (and not overheating) it turns off without warning, which as you know is very, very bad for your hardware. Near as I can tell I haven't contracted any virus, so I'm at a loss. Sometimes it shuts down in the middle of startup, and other times it takes several minutes.
Any advice?