File extensions that should never be deleted

[olopbob]

Thanks, I appreciate the help. I have been looking for good duplicate file cleaner (possibly with fuzzy logic) that would know which files to exclude but with no luck, although I've checked a lot of programs and done a thorough search. Any suggestions?
Thanks for the welcome, I'm with a couple other sites but get to much "reinstall or copy and spend days deleting then reinstalling again". I think thinking and learning are out of style. Did your registry setting disappear or am I missing something?
Cynical Bob