ConcertPreformer
A Windows application that allows you to bind a key with a sound file, giving you the ability to make songs using your keyboard as an instrument.
Installation
The app is still new, so no "releases" have been published, however, you can still download the last successful build here:
https://github.com/bitsol/ConcertPreformer/blob/master/ConcertPreformer/bin/Debug/ConcertPreformer.exe?raw=true
After downloading, launch the .exe and click the "Change key link to sound" button to start configuring your new tool!
Currently, this tool only works with .wav files, so you might have to convert some things.