Great music! A pity that some people haven't been able to hear it.
Here's how you can fix it.
The problem is that the File("src/ScreenOSMusic.wav") specifically looks for a real file on disk (in a real folder called "src"), not a resource that might be in a jar.
Two ways of solving this:
* Keep the code as-is, and supply the WAV (in a folder called "src") alongside the JAR instead of inside it.
* Keep the WAV in the JAR, and swap your File and FileInputStream code for a call to getResourceAsStream(). Resources might be files on disk, or they might be parts of a JAR (or theoretically other things).
Also, your game works on platforms other than Windows (I just ran it on Mac OS X), but not everybody likes RAR format archives. You could get more people playing your game if you link to a ZIP (or better still, just link to your JAR directly since a JAR is actually just a ZIP with particular files in it).