Enabling the Personal Firewall for Windows Vista

A personal firewall is a piece of software installed on an end-user's PC which controls communications to and from the user's PC, permitting or denying communications based on a security policy. Both Windows Vista, Windows XP and Mac OS X come with a preinstalled personal firewall that is very easy to activate.

Open the start menu in the lower left corner -> select Control Panel -> select Security
Click Windows Firewall On/Off and Choose On.
Close the Conrol Panel

There are a number of other firewall products on the market, make sure that you do not have 2 or more firewalls running on the same PC as this will cause all of the programs to malfunction.