Five free security software suites

It looks good too, with a blue interface that looks like it belongs on Windows, and clear icons to set its various options.

One of its biggest features it promotes is its LinkScanner option, which offers web-based protection that our sister title PC Pro says is one of AVG's "trump cards".

This checks whether the websites you are surfing are malicious, and as web-based threats are becoming more of a problem for internet browsers, this is a good addition that the other free software packages here don't have.

The free software package from Microsoft naturally loads up perfectly on a Windows computer without a long download like some of the other packages.

As such, it looks like it belongs on a Windows 7 desktop with a clean tabbed window and a system tray icon, and because it's a Microsoft product looks like it has very little impact on system resources.

In fact, it is one of the most low-key of the free software packages, and doesn't nag you like some of the other products to buy the paid-for version, as there isn't one. In practice, it is only visible as a fortress' icon in the system tray.

Unlike the other free software packages though, it doesn't offer as many features, such as a web-based threat scanner.

Also, it doesn't need to run on much memory, which actually makes it better to run on low-specification machines.

In IT PRO tests, Security Essentials did very well in detecting malware, picking up 96 per cent of live files.

Avira celebrated its 10th birthday in September, with a claim that it protects more than 100 million users from malicious threats.

This has a noticeably quick install, and with a good number of features compared to other free security packages.