Techies

[Man53]

Hey guys, I know some of you here can do a little bit of tech work before your PC's blow up, so I figure I'll ask you guys a question. My step-mom came to me about her computer problems, her comp randomly locks up for "no apparent reason" when she's playing a game, surfing the net, working with her "work-stuff" and simply when her screen-saver comes up. Also she claims to sometimes (rarely) hear the windows's "shuttuing-down" sound. I ran a diag and didn't find much, fixed the small stuff, but she still seems to have trouble. Any ideas?

*S* Thanks

Man53