Volume keyboard shortcuts stopped working

I have a 64-bit Gateway T-6828 running 11.0 Gnome, and my volume and player (play, stop, pause, etc) buttons just stopped working. I updated massively my libraries and I think it may have to do with this but I’m not sure.

They were working fine for about 6 months, so I’m pretty sure that it’s not a hardware problem. I already checked the keyboard shortcuts and they are correctly assigned, and also other keyboard shortcuts (for example to start a terminal) do work. Only the ones that control the volume, mute, play pause, etc. stopped working.

Also, When I ‘slide’ the volume up and down from the keyboard shortcut, the volume window appears and it actually slides up and down the volume level, but the volume-meter is grayed out and doesn’t change the volume. I have checked the mixer and googled around but can’t find anything helpful.

Does anybody know what might be going on here?

Thanks,