Windows 7: lock system

hello..i have pc in my home running for internet and gaming,i am wondering that the user attempting to delete the files and installed games,how can i lock the system so that even they are deleting the files after restarting all the files back again.and also how to unlock.please post the step by step guide for me.please thank..

I'm a little confused as to what you're asking. Someone is deleting your files and games when you leave your computer unattended?

oxymoron02,thanks,yes something like that,because sometimes i visit to the Internet cafe i'll try to delete the shortcut in the desktop,i notice that the shortcut are deleted but after restarting all shortcut of the games on the desktop back again,

They are probably running a program like deepfreeze.

usernameIssues..thanks,can you post here how to do that,coz iwant to do that in my pc,to make my system deefreeze..thanks once again

Deep Freeze, is a commercial software. There are free alternatives, the one I am familiar with is Toolwiz Time Freeze. I haven't used it myself, but here is a review.

Toolwiz Time Freeze allows you to safely test software

A Guy