16. IEToys

Add extra features to Internet Explorer 8 with this free collection of add-ins, most of which are accessible simply by right-clicking the page or selected text: hide distracting images from a web page, look up selected words in an online dictionary, encyclopaedia or search engine, and fix malformed web links. Note IEToys isn't compatible with IE9.Desktops

17. Desktops

Desktops
Too many open windows? Desktops enables you to organise programs and windows in up to four virtual desktops – switch via the Notification tray icon or by assigning hotkeys; perfect for comparing several open windows without having to resort to the taskbar.

18. PageDefrag

This tool enables Windows XP users to examine and – if necessary – defragment key system files when the PC is next restarted, giving their computer a performance boost.

19. Internet Explorer

Are you running the latest version of Internet Explorer on your PC? Windows 7 and Vista users should update to Internet Explorer 9 if this isn't the case: it's more secure, stable and – above all – much quicker than previous versions. XP users should download Internet Explorer 8, which is a far safer option than the outdated and insecure version 6 that shipped with it.Microsoft Fix It Center

20. Malicious Software Removal Tool

This is designed to detect and remove a wide range of known infections from your computer. It can't protect you against viruses in the first place – that's a job for your security software – but if something gets on to your system, it may be able to help with removing it. The Malicious Software Removal Tool is updated once a month through Windows Update, when it scans your computer for possible infections; to run it manually, download it from the link above.

21. Microsoft Baseline Security Analyzer

Give your computer, as well as any other networked PCs you use, a once-over for security problems with this free tool. The Baseline Security Analyzer works by verifying that your system is fully patched with the latest Windows updates, and examines it for specific areas of weakness. For example, it can flag up whether or not adequate protective software has been installed.

22. RichCopy

RichCopy is designed to speed up large file transfers over the network, mainly by copying multiple files at once to make maximum use of your network's bandwidth. It's aimed largely at power users – click Settings to see a bewildering array of options – but it can also be used simply by choosing your source and destination directories (click Connect to select your network destination), then clicking the Copy button to let it perform its magic.

23. Windows Search 4.0

Windows XP users jealous of how quickly searches are performed in Windows 7 and Windows Vista can benefit from the same super-fast technology with Windows Search 4.0. Once installed, allow time for your drive's contents to be indexed and then use the Search box on the taskbar to gain quick and easy access to all your precious files, wherever they're hiding.

24. AutoRuns

Start-up programs hit Windows performance twice over – firstly by extending the time it takes to start Windows, and then by hogging valuable system resources, giving your computer less to work with. Autoruns enables you to see what's starting with Windows, identify unknown items and disable or delete anything nonessential to make your computer faster. Windows 7 and Windows Vista users should run the program as an Administrator in order to make changes.

25. ClearType Tuner Power Toy

This enables you to calibrate your display to make your text sharper, clearer and more legible, which can only help those tired eyes. It's built into Windows 7, while Windows XP users can download a Control Panel applet from the Microsoft Typography website; Windows Vista users should use the online tool to calibrate their displays.

26. Microsoft Security Essentials

Can't afford to pay for security software? Frustrated with your existing free anti-virus tool? Then this could be the answer. Security Essentials is a lightweight, unobtrusive and most importantly free anti-malware tool that's rapidly become one of the most popular security tools for Vista and Windows 7 users. There are other freebies offering better protection out there, but if you're not the kind of person to put your PC at risk from infection on a daily basis, it should prove perfectly adequate.

27. Microsoft Safety Scanner

You think a computer's infected, but you're not 100 per cent sure. You need a free, regularly updated and above all portable tool you can run from CD or USB stick to quickly give that PC the once over to confirm or allay your suspicions. This is that tool. Microsoft Safety Scanner runs both quick and full scans of the target PC's hard drive, and is capable of removing any infection it finds. It's no substitute for the real-time protection offered by your existing anti-virus tool, but it's worth using as a second opinion. Note the tool expires after 10 days, ensuring you replace it with a version containing the very latest virus definitions.