Hi Mike,
Sorry to hear about your problems. I've installed VFP 6, 7, and 8 on locked down workstations by doing an XCOPY of the files on CD to a folder on my hard drive and then manually created a shortcut icon to launch VFP (VFP#.EXE).
Long term this is not the way to go. But if you're in a bind, this should at least get you going again. Note that certain features may or may not work. I personally did not come across any problems, but I was using these setups in a limited "emergency" debugging mode.
The long term solution may be to reinstall your OS and reload everything from scratch. It sounds like your registry was hosed. And possibly other parts of your operating system.
Good luck!
Malcolm