Please take a look at Don't Sleep
, a small program that can help either prevent or kick off "sleeping" of the monitor or pc. I have used it to prevent the screen sleep when I'm working on multiple boxes and I need to switch around, but also I have used it to make my wife's monitor go to sleep after 10 minutes which, for some reason, it would never do.
Turn on two menu options (Start Minimized and Start With Windows), then use its two tabs (Please Don't Sleep and Please Sleep) to set up the behavior you want by turning the tab options on or off. On my wife's pc I set it to turn off the monitor if no keyboard or mouse events in 10 minutes, but there are several options for what you want.
This doesn't have any effect on your power options, it just makes your PC do what you want.