:nerd: Audacity 1.2.6 on Windows 7 and the Compressor is set to default threshold -12 ratio 2:1 attack .2s and normalize to 0.

My saved Wav file is amplified to maximum without clipping. I open fiIe use the edit tool to select all of the track and then use the effects tool to get compressor, I preview and it is perfect, I then use compressor by pressing ok, and the final outcome is that it is not loud like the preview button when it is pressed.

The recommended version of Audacity for Windows 7 is Audacity 1.3.13.
The compressor effect in Audacity 1.3.13 is much improved over the 1.2. version.

More info:

This should get you along for loudness:

Have fun.