I had a a problem with my PC on which I fixed. But on putting back CIS 5.10 is shows up
Comodo Installer box with text saying Cannot install COMODO Internet Security Error: 1603. Fatal error during installation.
So what is this and how can I get it to install.
Regards
Nigel
Just thought I do some feedback to say. I found the fix.
It was a hidden driver under cmdhlp in the Registry that was locked up. The Driver was COMODO Internet Security helper
I removed it and now I am able to install CIS 5.10 without any problems.
Regards
Nigel
Thanks for the update with the solution Nige_40. Hopefully it will help someone down the road. 
Your Welcome HeffeD