Uninstall problem

I have read other posts on this subject and cant find an effective answer to my problem.
I have been running the firewall for months with no problems. I received an alert to reinstall the program to fix a problem. I downloaded the latest version and when I tried to run it, I was told the program was already installed and would I like to remove it I clicked ok and nothing happened. I repeated this process a couple of times with the same result and so I tried to remove it from add and remove programs with out success. After a great deal of fiddling about I managed to revove it from add/ remove programs and deleted comodo folder from C: Program files and all short cuts.

I then tried a fresh installation and received the alert that it was already installed and would I like to remove it when I clicked ok it still says the program is installed and so on. If I click to uninstall it nothing happens it just goes round and around. (:AGY)

Any help appreciated