If when you try to start Windows Firewall, DHCP client, or Diagnostic Policy Service, you get an error message:

Windows could not start the Windows Firewall, DHCP client, or Diagnostic Policy on Local Computer. For more information, review the System Event Log. If this is a non-Microsoft service, contact the service vendor, and refer to service-specific error code 5

Then you can download and and run the Windows Firewall Troubleshooter.

Specifically it will solve the following problems:
  1. Windows Firewall is not the default firewall
  2. Windows Firewall does not start
  3. Windows could not start the Windows Firewall
  4. Service-specific error 5 (0x5) Remote Assistance does not work
  5. You cannot access shared files and printers


To see how to fix the problem manually, visit KB943996.