Volume Mixer Problem

Hello guys,
So i got a problem on the Volumer Mixer.
All started yesterday after i decide to install my new speaker... now is giving a headache to fix to the way that was before.
Basically before i could control all the computer volume but now when i go to volume mixer there is a lot of stuff open and then i need to control each volume for each application...
I want to be able to remove all applications and be able to put louder my volume with only one slider.
here is a picture of the problem:


The Device is my Headset a Logitech G930. when try to turn the volume louder on this slider:

Doesn't get louder like the headphone used to get.
Well i hope anyone can help here, thank you very much.

That's for analog speaker output, you have USB headphones now, different ballgame. In Control Panel > Sound, you should be able to find those headphones and adjust from there. Alternatively, there should be a driver and program for them too, sou you could set them from there.