How to turn off the screen on a Lenovo Thinkpad?

I just got a new laptop and am already missing my Dell which had a single button to turn off the screen and nothing else (most importantly sound). I figured it might be a bit more complicated on a different computer, but I haven't found any way at all without downloading some questionable software. Therefore, my questions are twofold:

1) Is there any way to do it using just the keyboard or some function within Windows 7?
2) Is there good free or inexpensive software available that isn't malware, etc.

If you go to Control Panel\All Control Panel Items\Display\Screen Resolution on your computer then click connect a project it will bring up a menu then select projector only. BUT BE VERY VERY CAREFUL if it isn't actually connected to a secondary display don't go down this route because it can be very difficult to get the screen back on. The same menu may also be on one of your function keys.