How do I: Secure my home wi-fi network?

Most of us have stumbled into someone else's unsecured wi-fi network by mistake in search of a stable connection, but not all surfers are so benign.

According to an "ethical hacking" study carried out by a card-protection company, nearly half of Britain's home wi-fi networks can be hacked in less than five seconds, leaving the hacker free to hijack emails, steal bank account details and commit fraud.

We tend to think of hackers as sophisticated criminal networks but all it takes is a modern laptop and widely available software to breach most home computer networks.

Your first line of defence for your home network is its encryption, which secures the data transmitted between your PC and wireless router. Unfortunately, until recently the majority of routers were shipped with encryption disabled or only installed with WEP, an out-of-date encryption format.

If you haven't already, enable your encryption. To do this you need to connect your router to your PC with a LAN cable (from £5.99 at maplin.co.uk). Then simply open your PC's web browser and enter your IP address (normally found on the back of the router).

The interface will vary depending on the model of your router (see manufacturers' websites for more details) but if your computer is up to date – Windows XP or later – select the WPA or WPA2 form of encryption and create your own unique password of at least 14 letters and numbers. If your router only supports the insecure WEP format check the manufacturer's website for a firmware update to support WPA.

And for additional protection consider running a software firewall on your PC. A good free download is Zone Labs' ZoneAlarm, which is reliable and free to download (zonealarm.com).