I've just upgraded to XP home, and it says it comes with its own firewall. Is this sufficient, or should I install my own as well? I used to use the free zone alarm, will this still work with XP, or will it conflict with XP's own version? Any advice will be welcome.
Diodorus Siculus is right. you would be amazed what programs want net access. get something like zone alarm and you'll get a pop up when a program wants net access then you can decide to grant it or not.