One of the best mp3 computer software players is Winamp.
The sound quality is good and the options are numerous. Lots of bells and whistles, eq, skins, etc can be found in the plug-in sections. Its easy to setup and use as well.
However, it's best to use version v2.78. The latest version (3-Beta2) is really good, but is unpredictable due to the fact that it is beta software. Best to use v2.78 for the school show as its performance is rock solid.
Get it at h**p://w*w.winamp.com/