Volume Control Button On Task Bar

I am using XP Pro and up until recently when I clicked on the volume control button in the task bar on the lower right hand side of the screen, the button would open up and I could raise or lower the volume with the slider and right click on the button to get an idea of how loud the volume had been increased or decreased. After hooking up a USB turntable and installing the accompaning "AudaCity" software the only sound I can get when I click on the button is the "mute" sound even though there is no check in the "mute" box. It doesn't matter how high or low I raise the slider, the sound is the same; mute.

That really would not be a problem in as much as I am still able to play all .wmv, .wav, .mpeg, and .mp3, etc. files and the volume control button works to control the volume on all these files. The problem is that I was able to record a song from two different albums and save it to "my music" folder, but when I tried to record another song the following day the turntable would not record. I discovered it was not working because there was no sound and thinking perhaps I had muted the PC I checked the volume control button and discovered then there was no sound when I clicked the button.