Cubase 7 mutes computer sound

Hi, I use licensed cubase 7. On the very moment I open Cubase, all sound in the computer mutes. All sound settings in the computer seems ok, and still no sound (doesn’t matter what input I use. Headphone/Speaker).
It is solved only when I restart the computer. I will very much like some help with this problem!

This isn’t a cubase issue; or an issue at all- its how your interface operates.

Cubase is always hungry for audio. To deprive the spoilt child and reclaim what’s yours:

from the menu: Devices/Device Setup/VST Audio System
in the righthand panel make sure the first tick box is checked (Release Driver when Application is in the Background) and click “Apply”.
…now you can have your just deserts.