Runtime 8 to Runtime 9, no Win2K

[BNibe]

I have a runtime solution that I distribute annually to 100 users (entry/registration for an event). It has worked well when created in Fm8. Since it wouldn't work on Vista, I upgraded to Fm9 and re-distributed. It works on XP and Vista, but won't work on Win2K (I didn't know we still had them.) So I went to my old computer, re-compiled the files using Fm8, and sent that out. It still won't work on Win2k. Is it because I've opened the original files in Fm9? Is there a work-around to get a version like the previous one? I can't go back to last year's file because it's an annual update with changes, so this year's solution isn't the same as last year's.