WinAmp
WinAmp allows you to play MIDI, MP3, WMA, Ogg, WAV and a number of other popular multimedia files. It is freeware available for all versions of Windows. Click here to download WinAmp
Windows Media Player
This software should come installed on your windows PC, simply type "wmplayer.exe" in the Run command of your Start menu if you cannot find it. For the latest version, download it from Microsoft's official website. Click here to download Windows Media Player
