screen locks up, weird problem

[n19htmare]

I have XP Pro SP2 installed on my machine (in sig).
Now, when i leave the computer on and screen unattended, all the windows lock up.. I can move the mouse around but can't click on windows or links and what not. Now if i do Ctrl+Alt+del, as soon as the Windows Task Manager window pops up, I can click on links and so on.

Why does it lock up?

thanks

 

[D1gger]

Are you using a third party screensaver?

Perhaps it is a power saving feature. I would check the settings in Control Panel \ Performance & Maintenance \ Power Options and disable the power down and hibernate features.

 

[n19htmare]

no third party stuff, it just does it out of no where. Even on a fresh XP install