how to disable password

hi to all…

i have a PC having an OS of windows 2000.
my problem is if i leave my PC unattended even just about 10 seconds there is an popup window will come out and says “the computer has been locked only the owner can unlock,how im going to disable it.i find in control panel but i can’t locate it.i felt this appointed it because all the times will come out..

help pls.

john