Can't able to open apps after installing a new version of Comodo Firewall 6.0

After i installed Comodo Firewall 6.0, i can not able to open any application media player,browsers,download manager etc… especially exe files.
Then i tried to uninstall the firewall.
After i uninstalled everything works fine.
Again tried to install it but facing a same problem.

Currently running on Windows 7 Ultimate.

Strange. Do you receive an error message when you try to open these? If not then please describe what happens.