I had a problem with Comodo Firewall version 5.0.163652.1142
The message I was receiving from both the status/tray icon and Summary page was “Comodo Firewall is not working properly!”
At this point it needs saying that I think Comodo is a great product and I appreciate its presence as a free and purchasable product. It received high marks from reviews and my own experience. I wouldn’t have tried so hard to fix the problem I was having with it, if I didn’t think it capable 
After noticing the icon which consisted of an exclamation point inside of a triangle on the Comodo shield icon I searched the installed help file to see what this meant, but couldn’t find the answer. Then, I went to the forums. The relevant post I read suggested using an INF file to install a network service under the repair folder in the Comodo installation. The repair folder didn’t include such a file.
(To be accurate the fix was posted a couple years ago, but it was the only hit I could find. It was discussing version 3 and the tech said with version 4 it would be fixed. I had upgraded from version 3 and then had this problem.)
At this point I uninstalled version 5 and reinstalled it.
For 3/10ths of a second this worked. But less than a second later the icon reappeared during the boot process. So then I uninstalled it and put version 3 back on, which had been working fine before the upgrade. (The upgrade from version 3 to later version was done by clicking the check for upgrade button, so I don’t know if that install routine uninstalled the previous version or just upgraded, but all subsequent installs were preceded by an uninstall) But the problem with version 5 was now effecting the installation of version 3, also.
Long story short I did a lot of uninstalls and reinstalls and reading to see if anyone had recently experienced the same, but nothing worked.
Finally it hit me (glory to God!) that I had seen when things worked, under the device manager tree, some low level drivers for Comodo. I was able to locate them again, and there was no initial indication that they were broken (there was no tell-tale exclamation point in a yellow circle that windows often puts for misbehaving devices) Upon clicking it there was an error code which I have forgotten, but believe it was 10.
I deleted all three Comodo drivers which I would have thought would be removed upon uninstalling the app, but was not.
At this point, after reinstalling version 5.0.163652.1142, things are working perfectly once more.
I write this in hopes that anyone else who has experienced this and if it is not covered elsewhere–might find this helpful.
One must have device manager open and then select Show hidden devices under the View menu to see the Non-Plug and Play devices. The Comodo Internet Security Firewall Driver which goes by the service name Inspect was the important one, I believe. There’s also a Helper driver and a Sandbox driver, the latter of which was not put back with the latest reinstall.