The majority of the sheet music on the site is in ZIP format when it's first downloaded. What this means is that the file has be compressed for use on the Internet. The first thing you'll need to do to open these files is use a program such as WinZip (free download from http://www.winzip.com) to decompress them. You'll then most likely be left with a file with a .mus extension. These files were created using Finale, a music notation program created by Coda Music. To open these files, you'll need the Finale Music Notepad, which can be downloaded for free from http://www.codamusic.com. Some sheet music, including many of the samples in our store are in Sibelius Scorch format. Again, the plugin to view/listen to these files is a free download. You can download the plugin from here.