As far as Harmony Assistant or Melody Assistant from Myriad is concerned, they have a freeware player that will play back music files in a browser. All you need to do is download a player from their website. Said player could also be bundled with Digital Tradition, with permission from Guillon brothers of course. They seem to be quite approachable.

The real problem is finding someone with Melody Assistant or Harmony Assistant who is willing to convert 4000 tune files! Personally, I have Melody Assistant, but I am not making any promises ...