The built-in firewall is rubbish. It seldom seems to stop anything. Also, the ZoneAlarm firewall is much more stable, does not slow down the internet connection, uses very few resources and is better than the Windows Firewall in more ways than one. And what do u mean "came with the OS"? Just because something comes with an OS, doesn't mean it's great. Windows Media Player comes with the OS, but most people use other programs to play movies or songs. Internet Explorer also comes with the OS but it's one of the worst browsers ever made.