It's a gift.
Like I said, if you already have a professional virus scanner or firewall program (i.e. Norton or McAfee) then you dont need these. These are for those that do not have any protection or don't have the money or time to go out and buy the professional software.
You truely need both programs, one is not better than the other and they both do different things. An anti-virus protects your computer from known viruses. It will kill the virus when it detects them. A firewall on the other hand does not kill anything. What it does is it seals up ports (logical holes in your machine in which data flows in and out) and monitors which programs are trying to connect to the internet to to send data. This will stop all hack attempts and worms (viruses that enter your machine through open ports) from entering you machine but it will NOT stop viruses. It will prevent viruses from sending your private information from your machine back to the hacker, but it wont stop you from downloading them. Think of it as in the forms of birth control, for best results you're going to use more than one form of birth control. Hey shut up, it hard coming up with an analogy everyone can relate to.
Note: If you got the Zone Alarm program, put it on 'Learning Mode". That way it learns with programs you use frequently and which programs you dont. Be aware that the first couple of days will be a bit of a bitch as it gets settled in.