A common way to lock your computer (assuming you are running XP) is to hit the Windows + L key simultaneously.
But what if you don’t have a Windows key on your keyboard? There are a couple of other ways to do it:
My choice is to create a shortcut on your desktop as you will probably use it over and over. Right click on an empty area of your desktop and click on new>shortcut. Enter rundll32.exe user32.dll, LockWorkStation and click on next, name your shortcut and click finish. That’s it.
If you want to change the icon, right click the shortcut and go to properties>shortcut>change icon. Browse to the moricons.dll in your system32 folder to see a large number of cions to choose from.
A quick and dirty way to achieve the same result is clock on start>run and enter rundll32.exe user32.dll, LockWorkStation in the command dialog box.
If you have fast user switching enabled, another way is to bring up task manager, click on the shutdown menu, and select switch user. Same result.