>>VFP 6.0 does not work because of a resource file version conflict.
You have a foxuser.dbf from some other version in your path, I think you could just remove that foxuser.dbf from the path and you should be fine.
Otherwise you could start 6.0 it by adding:
RESOURCE=OFF
to the CONFIG.FPW (You might have to create the file)
BTW I would consider backing up that machine, reformating the HD and reinstalling from scratch. Reinstalls over a previous install tend to be flakey.