Two monitors control

[marksandsoy]

Hello,
I have a second monitor on my laptop. I want to use only the second monitor and turn off the laptop monitor. I thought there was a combination of keystrokes that would change between using the laptop monitor, or the second monitor or both. Can anyone tell me of a keystorke combination that may do this?
thanks

 

[Ijack]

I doubt anyone can answer that without knowing the make and model of the laptop. The instruction manual should detail that information.