Installing and running a firewall

There are various ways of installing a firewall on Windows xp, one way is by running the fiewall sofware that comes with the PC or version of windows, but not all PC's have standard firewall software so its possible to download firewall software from the internet:

The third way to install a firewall is by using a disk, some firewall programme that need to be bought are sold using disks but have the same instalation files so the setup is the same as downloading the programme from the internet.