| There are several ways to lock your Windows XP computer, but all of them use the same command line. The method you choose is a matter of personal preference.
1. via the keyboard
The easiest way to lock Windows XP is by simply pressing the Windows logo key and the letter L (for Lock) on a Microsoft Natural Keyboard or any other compatible keyboard that includes the Window key. Doing so will pop up the Unlock Computer Password box.
2. via a Shortcut.
If you don't have a keyboard with a Window key or simply don't like the keyboard method, then here's how you can make a desktop shortcut to lock your computer.
Right click an empty area of your desktop, choose New/Shortcut and enter this line as the command line:
rundll32.exe user32.dll, LockWorkStation
Click Next. Name the shortcut whatever you prefer and click Finish. That's it.
If you'd like to change the icon, just right click the shortcut and go to Properties/Shortcut/Change Icon.