Laptop Energy Saving When Downloading
If you wish to blank your screen when you are not working with the computer, choose the "Blank" screen-saver.
This is done at Start > Change screen saver. You can test it using the Preview button.
Also try Nirsoft (nirsoft.net) Monitor OFF (batch file and monitor is completely black.
Nirsoft app is nircmd.exe
C:\Applications and Technical\NirCommand
Then make a batch file:
"c:\applications and technical\nircommand\nircmd" monitor off
This is a nice method because you can turn the monitor OFF on demand when you are finished your work.