How do i

Hi i have tried to install comodo firewall on my system after reading about it but i installed the pro version beta from filehippo and then realised i should have installed the other i uninstalled the pro version and installed the other one but they were both showing in add/ i tried to uninstall both and re install the correct one but the pc wont let me re install .when i try to re install it tells me its already on the pc and would i like to uninstall and i click yes yet nothing happens i have looked in the add/remove but its not there could someone please advise me of what i need to do to completly remove and do a fresh install.hope that makes sense.