A House of Lords select committee once branded the internet a lawless Wild West. Users must guard against viruses, spyware (which allows crooks to access your data or even hijack and use your computer) and a plethora of scams. With a little research, however, keeping safe online is straightforward and free. Here is Times Money's guide to protecting your PC.

Upgrade your system

The newest version of an operating system is the safest. Windows users with ancient hardware should upgrade to Windows Vista or Windows XP with Service Pack 2. It may be more cost-effective to buy a new computer with this included. All users should download free security updates at www.windowsupdate.com. Set your PC to download them automatically by navigating to "control panel", then "system", then "automatic updates". You should also download the latest version of Internet Explorer or Firefox, which offer some built-in virus protection.

Install a firewall

Mircrosoft gives Windows users a free firewall, which is an adequate first line of defence for most people. This keeps out bad hackers, some viruses and some spyware. Go to "control panel" then "security centre" to activate it.

Use antivirus and anti-spyware software

Most new PCs come with a free trial of Symantec's Norton AntiVirus. Updates cost about £20 a year when this ends. However, Andrew Ferguson, of Thinkbroadband.com, the specialist website, says that free alternatives, such as Grisoft's AFG, available for download at free.grisoft.com, are adequate. Once virus protection is in place, you must tackle spyware. Microsoft's free Defender software should suffice. Look for this in your PC's "all programmes" folder. If it is not there, go to www.microsoft.com/download for a free copy. You should set all antivirus and anti-spyware software to receive "automatic updates". User feedback on security products can be found here.

Secure your wireless network

If you have a WiFi, or wireless, network, secure it by switching on the built-in encryption, renaming the network and switching on "MAC filtering" to restrict access to trusted computers. Get Safe Online, a government website, has detailed guidance here.

Back up your data

However well-protected your PC, it is important to back up your data to CD or DVD at regular intervals. This means that you will not lose important files if your computer is stolen or damaged. Keep these discs, as well as the operating system discs that came with your computer, and any software discs, in a safe place away from your terminal. For more advice on how to back up your data, click here.

Be savvy

The precautions above should be combined with common sense. You should keep your PC in a secure location, not by an exposed ground-floor window, for example. And once online, be wary of scam e-mails. If something sounds too good to be true, it is. Likewise, avoid giving out personal details that could facilitate burglary or identity fraud. When you must disclose your address and credit card details to make a purchase, do so over a secure server at a trusted website. Avoiding pornography and offensive material should be straightforward. If you do stumble across content that you believe to be illegal, however, report it here.

If things go wrong

All PCs connected to the internet are vulnerable to viruses and spyware. These can cause numerous problems, including a general slowing or failure of your system. Firewalls and antivirus and anti-spyware software cut the risk, but they cannot remove it. If you suspect that your computer is infected, consider this advice or, for £99-plus, call a geek on a scooter to fix it.

See the Metropolitan Police website for advice on reporting internet crime. Be aware, however, that British investigators have no authority to pursue most scammers based overseas. Scambaiting offers some consolation.

Five news stories

Thousands hit by tax return phishing scam

Banks let us down on fraud protection

Websites sell bank data and Pins

Careless Facebook users open to identity theft

Cybergang raises fear of new crimewave

Five features

Cyber crime: bigger than drugs and aimed at you

Secure your WiFi

Be on your guard

Make your tired old PC run like new

Keep yourself safe when you bank on the internet

Five websites

Get Safe Online

Think Broadband

Think U Know

Microsoft Security at Home

419 Eater

Five videos

What can go wrong?

Why secure your WiFi network?

The Mac Perspective

Scamming the scammers

Is your son a computer hacker?