Just to recap, I've tried the update program, then I uninstalled, removed all of the registry items that I could find, reinstalled, then tried the manual file, both stop at the same 95% on swkotor2.exe with a bad checksum. I redid both of those steps while only disabling my antivirus, but that didn't work either. I will try to entirely shutdown the .exe for my antivirus programs and see if that helps. I appreciate the help. Like I said, I know that that this is an old problem because the the other strings are all from quite awhile ago.
I'll reread through the other strings to see if I missed anything. If not, maybe I need to buy it again, who knows.