Thanks for your suggestion, but I am a bit fuzzy regarding "Delete all folders ... including hidden ones". I believed that I had done that but there must be folders that TTAX has accessed (either created new or reused) to save a copy of the registration key. I'd really like to have an idea the folder name and/or location that TTAX will have used for saving a copy of the program registration key (so I can delete it). From your answer, and position as TTAX expert, it sounds like you know for sure that TTAX has not put anything in the Window 10 registry with program key information (which is a big relief since I was reluctant to go messing there). I've got copies of TTAX on this Win10 PC for earlier years so I don't want to go messing up these earlier TTAX programs by deleting too much in case I need them for any problems which could conceivably occur with those returns). In addition to the folder path name I provided as installation time are there other folders TTAX access (like for application data). Thanks again. TJ
