Is there any way to make Fn+F3 switch off the monitor, provided one does not have Lenovo Power Manager installed?
I guess if the hotkey utility is installed then you can tweak the registry. Start "regedit" and go to:
The "File" value in this key determines what will be started when you press Fn+F3. In my case it is:
which shows the Power Manager's power schemes popup window (or turns the display off depending on configuration). If you put the LCDoff there, it should work. Also consider using my equivalent
which doesn't cause a console window to pop up and it turns off the ThinkLight as well.
You may still need the Power Management Driver or whatever it is called. I'm not sure but it's possible the hotkey utility needs this to work.