** THE FIX **

I gave up and spent the $245 for Microsoft Developer Phone Support. Turned out that when I disabled the Norton Anti Virous I didn't disable all of it. The MS guy had me uninstall it and the problem went away both here and at the client's office. Seems that Norton was trying to open the files for some reason and because the 1GH PC is so fast it was stepping on VFP. I reinstalled NAV and just turned off the check box marked check files when opened or something like that and that was enough.

Thanks to all of you who helped.
John.