lock pc just by double clicking mouse

You can lock your XP workstation with two clicks ofthe mouse.
Create a new shortcut on your desktop usinga right mouse click, and enter 'rundll32.exeuser32.dll,LockWorkStation' in the location field.

Give the shortcut a name you like.
That's it -- justdouble click on it and your computer will be locked.

And if that's not easy enough, Windows key + L will dothe same.