Instead of pressing CTRL+ALT+DEL or windows + L to lock your machine you can lock your machine using a single mouse click.
Just Follow these simple steps >>
1. Right click
an empty spot on the desktop, point to New and click Shortcut.
2. In the Create Shortcut dialog box, type the following in the 'Type the location' of the item text box:
3. Click Next
4. In "Type a name for this shortcut", type "" (any name as u wish) and Click Finish
5. This will Create a shortcut in your Desktop.
6. Now each time when you want to lock the computer , Just click on this shortcut.