Here's an alternative way to lock your Windows computer.
- Right-click an empty spot on the desktop, and select New → Shortcut.
- In the Create Shortcut dialog box, type or copy rundll32 user32.dll,LockWorkStation into the "Type the location of the item" field.
- Click Next.
- In the "Type a name for this shortcut" field, type "LOCK" and then click Finish.
- Windows will create a new shortcut icon on your desktop.
Now you can just double-click on the icon to lock your desktop.