I have an external sound card plugged in through USB, which connects to my 2.1 speaker system. I have a pair of headphones plugged into the headphone jack. Whenever I switch between the two, I hold option down and click the sound icon to quickly switch between them. Everything was working fine before I had my HDD switched out, but now I am having problems. If I am playing, let's say a Youtube video through the sound card/speakers setup and change to my headphones, no sound from the Youtube video comes out of the headphones. Clicking the volume toggles up and down play through the headphones fine, but nothing in the browser. I have to close the browser completely and pull back up Youtube for it to work. Has anyone else experienced this? It use to work fine.