Do I Need A Firewall?

I just got the Charter high speed security sweet, it has a firewall, which i don't really know anything about firewalls, do i need to use it? Also the antivirus is set on "normal", should i set that to "high" where it scans more files or is that not really necessary?

Ok, It is definately neccessary to use a firewall… With the antivirus settings, I would set it to high, and if your computer slows down too much, then you can set it back wng