Options - File Types

The users of Windows XP, Windows Vista and Windows 7 have two choices to set WavePad as the default programs

Use the menu Tools -> Option -> File Types
Select from this list of file types those that you would like to open by default in WavePad. For example: if you were to select .mp3 here, this would mean that every time you double clicked an mp3 file, it would be opened using WavePad.
Use Windows Operating System's Control Panel -> Default Programs

Note.: Windows 8 and after DO NOT have File Types page on Options Dialog. If you are the users of these platforms, and would like to set WavePad as the default program, you have to use Windows Control Panel -> Default Programs.