hello, I'm using windows vista.. my computer keeps LOCKING and i don't know what to do to remove it.  i try to do the Ctrl+Alt+Del but it ddnt work.. is there anyway how to unlocked it?.., thank you!!!What exactly do you mean by locking ? ?Freezing?
Click here to find out what information I should add when submitting a question?if you mean locking as in needing a password you can do this

-Run
-type cmd (ENTER)
-type net user (ENTER)
-type net user (your account name) (ENTER)          *DONT PUT BRACKETS IN FOR YOUR ACCOUNT NAME!
-type net user (your account name)_* (ENTER)
-type new password (ENTER)
-confirm new password (ENTER)

**when i wrote _ that means hit space.
**DONT achually type (ENTER) that just means hit enter.
**Your account name is the name you log on to.

If its Freezing, well then PRESS CNTL AlT DEL when you get on, keep a look out for WHATS running on the PROCESSES tab, then when it freezes, note the process that was running the most at the time of the freeze, next time you log on, do a google search of the process. If it is a non Essential process, ENd it. If it is an essential process, do a REGISTRY check to see if its a worm or something.

Hope this helps.