KN2000 change sounds on Midi files (Virgin needs help)

Hi All, Im a virgin to this site, but hope someone can help. I have a KN2000 and loads of general midi files on disk, but the instruments they are played on are dam awful.
When I change a sound, and re-save the midi it looses all the changes I make.. What am I doing wrong, or is there anyone who can advise me on how to do this?

Thanks
Garry

You may want to post your question over at the General Arranger and Technics forums here.

good luck,

-ED-