M1210 broken mute button

The mute button on my M1210 seems to be buggy as of today. I first noticed the problem when listening to a podcast on iTunes while browsing with Firefox. iTunes was operating in the background, and I hit the mute button to listen to someone near me, but the computer didn't mute completely. It only muted for a fraction of a second and then went on with sound. I had to pause iTunes. Upon further examination I discovered that this only happens when I hit mute and iTunes is in the background. If I'm focusing on iTunes in Windows and hit the mute button, the system will mute fine.

I also just discovered the opposite problem with Firefox and web based sound. I was at a friend's Myspace page which had music, and I tried to mute my system briefly. Same problem - it only muted for a fraction of a second and then went on.

The only recent change in my system I can think of that may be connected is that I just installed the latest version of iTunes (7.1.1.5). Any ideas?

 

i would reinstall quickset for starters

 

Good idea, and something I should have done anyway as I didn't have the latest version. However, that hasn't fixed the problem...