New 4K monitor won't show picture.

[Lodlike8]

I just plugged in my new 4K monitor, I have a GTX 960, and as of now nothing shows except my mouse, I don't know what is happening!

 

[ThatVietGuy]

Is there another monitor plugged into the GPU?

 

[Wiz33]

You using DP? or HDMI 2.0? For HDMI 2.0 you need a HDMI 2.0 cable.