I have been using Comodo firewall and love it. For some reason the Comoco firewall pro was removed (I blame the kids), and now I can’t reinstall it. There doesn’t appear to be any Comodo firewall pro installed according to ‘control panel’, ‘add or remove programs’. The Comodo firewall folder in the task bar is . If I try to reinstall Comodo firewall from the website, the software downloads then I get a message saying that Comodo firewall pro is installed on the system and do I want to uninstall now? Following either option leads to a nothing. No crash, no progress, just nothing. How can I reinstall?
Go to Start → All Programs → Accessories → System Tools → System Restore. Choose “Restore my computer to an earlier time…” and click Next. From the calendar, choose a restore point when you know the firewall was working properly and then click Next. Follow instructions onscreen to close running programs and then click Next. Windows will reboot and wind back the clock to the time and date you chose.
I’d suggest you password protect your Administrator account(s) so that the kids can’t logon with any of them and do the same thing again. 
Hi book, welcome to the forum 
Read this topic :
https://forums.comodo.com/faq_for_comodo_firewall/manual_uninstall-t5326.0.html
From here :
https://forums.comodo.com/frequently_asked_questions_faq_for_comodo_firewall-b32.0/
I hope it will help you
Greetz, Red.