Lock Your Desktop Quickly in Win XP

Simply press the Windows key & the L key at the same time.

Also, if you would like to add an icon to your "Desktop" or "Quick Launch bar", right click on the desktop, select "New", then "Shortcut", then enter in the this command line:

rundll32.exe user32.dll,LockWorkStation

Then name it something like, "Lock Workstation" and your short cut is created. Drag the shortcut into your "Quick Launch bar" and you're one click away from a locked workstation (if your user account has a password of course).