Quote Originally Posted by Slug For A Butt
Without a more detailed description, I'd say it could be anything.
Not all antivirus scanners pick up everything, you may have a horribly fragmented hard drive, you may have a hardware problem, you may have a bad stick of RAM, you may have an overheating PC, you may have a poltergeist prssing the reset button when you aren't looking... anything!
What are you doing when it locks up? Are you using intensive games, internet, art packages or does it just randomly freeze?
If you really don't know when/why it's freezing, a reformat and fresh install of windows may do the trick nicely. If not, it's probably hardware related. Windows accumulates so much shit over time it is unbelievable, and the odd backup/reformat/reinstall can do wonders.
It's usually the internet or when she's looking at her e-mails. She doesn't play any games.