Is there a master reset for the music database?  Things get really crazy when you start to make manual entries sometimes.

Would be nice to reset the music database and let the system perform the constuction of a new database again,

You can delete the database, that's about as reset as you can get :) 

Delete or rename: C:\Users\{you}\AppData\Local\Microsoft\Media Player

This also stands no chance of deleting the actual media files, unlike a slip/mistake with deleting from inside Media Player itself.