Media Player Classic

Wikipedia
Media Player Classic (MPC) is a compact media player for Windows. The application mimics the look and feel of the old, light-weight Windows Media Player 6.4 but integrates most options and features found in modern media players.

In conjunction with the Combined Community Codec Pack (it's included here), it should be your first choice for playing any multimedia file on Windows and not that overblown WMPlayer included in that OS.