In our previous tutorials about the Windows Firewall we've shown everything you can do with it: beginning with how to enable it, accessing defined rules, creating new ones, checking advanced reports and defining advanced communication rules. If you've done lots of configuring on it, something might stop working at some point. In such cases, it would be best to reset all rules to the default ones created by Microsoft and start from scratch. In this tutorial I will show how to do just that.
First, open the Windows Firewall window. In the right-side panel, click on 'Restore defaults'.

In the 'Restore default settings' window, click on the 'Restore defaults' button.

You are asked to confirm this decision. Click Yes.

You will be returned to the Windows Firewall window and all rules will be reset to their initial values.
NOTE: the above procedure works only if you are logged in as an administrator.
Conclusion
Resetting the Windows Firewall to its defaults is very easy. For more info about this tool and how it works, don't hesitate to check the articles recommended below.
Related articles:
Gain Additional Control by Using Windows Firewall with Advanced Security
Manage Rules in Windows Firewall with Advanced Security
Windows Firewall - How it Works and How to Enable or Disable It
How to Manage Windows Firewall Communication Rules
Network Locations Explained