If you have  a Windows XP machine which is not part of a domain and you’re unable to switch on the firewall because of the following message:

For your security, some settings are controlled by Group Policy

The fix is to :

  1. Click Start, Run and type “regedit.exe”
  2. Backup, then delete HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\WindowsFirewall
  3. Restart PC