iGain is distributed as either a zip file or Microsoft Installer (msi) file.
iGain requires iTunes version 4.6 or later. If iTunes is not found on your PC, iGain will not start.
Extract iGain.exe and iGain.chm into a directory of your choice. Then create a shortcut from iGain.exe to your desktop and/or Start menu.
iGain requires, but does not include, either MP3Gain or AACGain. If neither of these programs is found, iGain will not start up.
Download either of these programs, and place the executable file in the same directory as iGain.exe. If both AACGain and MP3Gain are present, AACGain will be used.
Double-click the msi file to begin the installation process, then follow the prompts. AACGain will be automatically installed, there is no need to install it separately.