your only recourse is to contact support.
it may be that although you ran the program uninstaller, and manually deleted the files recommended by TT, there may be entries left behind in the windows registry blocking reinstallation. . don't know about Macs or Apple computers
have you deleted items from the program data folder and some others that TT says you should delete. They are hidden.
to unhide them choose tools (at top of any folder) - then folder options - then view then check show hidden files, uncheck when done
have you tried reinstalling using the run as administrator option?