The one-way firewall

Windows' built-in firewall has always suffered from the same flaw:  although it blocks suspicious stuff that comes in, it does nothing about what your PC sends out.  Since an infected PC can mass-mail spam and forward your credit card numbers to someone without your better interest in mind, that's an important shortcoming.

Vista supposedly fixed this problem with the addition of a firewall capable of watching and blocking outbound traffic.  But that capability is turned off by default.  And Vista's designers forgot to put the controls that turn it on in a place where you're likely to look for it:   the Windows Firewall Settings dialog box.

Here are two solutions:

1.  Go to the secret place where you can turn on outgoing protection:  click Start,  type firewall, and select Windows Firewall with Advanced Security.  Click Windows Firewall Properties. The first three of the resulting dialog box's four tabs contain an Outbound Connections drop-down menu. In all three, select Block.

2.  Get another, better firewall:  Even with two-way protection enabled, Windows' firewall is a feeble guardian.  On the other hand, the free Comodo Firewall Pro came out tops in independent testing, even compared with well-known commercial products such as Norton Internet Security (according to Matousec's Firewall Challenge).