Microphone bar raises by itself!

[RedRooster]

My girlfriend and I are both using Messenger 4.6 to voice chat. But for some reason, the sound bar for the mic always raises by itself if you lower it. It doesn't cause a problem on my side, but for my girlfriend it does. Each time the bar reaches the end, you hear a really low pitch noise. The only way to avoid it is lowering the bar before it reaches the end. A real pain to do! She's on Win95, with an old sound card. Her mic level in the windows sound control is low also.

Thanks