Please do not hijack another users post - it is bad forum etiquette.
Create a new post if you have an issue with the software, read this post before posting and give more information - in particular:
Computer specification include processor make/model, quantity of RAM, Graphics cards used if any, Windows version.
Windows version
Music Maker fullname and version as found under Help, About
. . . . at least I was able to compose one piece of music before it died completely . . .now the fact I purchased this extra instrument doesn't even show up on my profile anymore
This suggest that something has changed on your computer, has Windows been upgraded or updated?
Are there any other issue with the Synthesizers in Music Maker or is it just this one ?