Sound On/Off

I have a fairly new computer, about two months. Intel Q9550, running Win Vista 64 Home. I have speakers plugged in and I also use a USB headset, Logitech Chat Pro.

I recently found out that if I switch between my speaker and the headset my sound will stop. The sound is there when I start what ever program, does the same thing in all programs, but will stop if I switch to something different.

It doesn't matter if I'm streaming a video from Youtube, playing a game, listening to music, etc. If I start the program and my headset is on sound will stop if I switch to the speakers. Same thing if the speakers are on and I switch to the headset.

I have to stop the program and restart it for the sound to switch to the other output.

When I first got this computer it worked fine. I could plug in the headset and the sound would switch, vice versa if I went to speakers from the headset.

Any ideas on what may have changed or what to check?

Thanks for the tips and advice.