Problem installing latest version - even after uninstalling prior one

I was using Comodo Firewall last month & then uninstalled it as normal. Went to install latest beta version & keep getting message that it is still installed. Choosing either option offered - Uninstall or Not - causes the installation process to abort.
Would appreciate any suggestions.

Rob

pls install the latest stable version. Beta’s are out of date and stable version has superceded it until the next beta relase.

Melih