Audacity Forum

If this helps, you'll also notice that when you use the slider on the amplify effect, the OK button will gain focus and go grey, affecting enabling the effect and disabling it. The point at which it goes grey is when your amplificatin dB's has gone too high. When this happens, slide the control over...

I'm having the same issue. I did some research on the internet and I believe this is an issue with Windows 7, both the 64 and 32 bit versions, and the use of their standard USB Audio Codec. It seems as though there are a lot of people that are using USB devices, like turntables, and getting static, ...