reinstalling firewall

hello i had to format my hard drive and now i am trying to reinstall firewall but get a msg saying i have an older version of installer,i have done a search of my pc and can find nothing with comodo.
i saw some instructions on faqs of how to uninstall but can not seem to be able to do it,any help please in laymans terms?
thank you.

I would suggest cleaning out the Registry.

You may do so ‘by hand’ if you like. Go to Start/Run and type in “regedit” (no quotes). Search for Comodo Firewall entries (try each word individually); make sure they are related to the firewall (in the event you use any other comodo software that you don’t want to mess up), then delete.

When manually editing the Registry in this way, it is a good (no, an excellent, or even mandatory) idea to FIRST go to File/Export to generate a copy of the entire Registry, in case you inadvertently hose it. Double-clicking that exported file will restore everything to that point in time.

You may also use a software such as RegSeeker to automatically clean out any old/rogue/orphaned/otherwise unnecessary entries. With these types of applications, be sure to use the option to create a backup of the registry prior to removal of said entries.

That should take care of it.