I had to reset my Preferences in LR due to filmstrip problems. When I do a editi-in in LR to edit in Topaz, the topaz products do not show. How can I get LR to recognize topaz plugin?
Resetting preferences wont affect your external editors. Sounds like you deleted your appdata.
See this article to add Topaz Filters, you will probably need to either recreate the external plugins or re-install.