The typical Registry is a complex database holding thousands of settings for both Windows and any installed applications. Unfortunately it'll probably also be cluttered with broken file associations, missing Startup programs, invalid ActiveX control references and other redundant entries left over from long-uninstalled applications. This junk can build up over time, consuming valuable system resources, affecting PC performance and occasionally even causing system crashes. Unless, that is, you take action with a cleanup tool like PC Tools Registry Mechanic 7.

At the core of the program is a speedy scanning engine that races through the Registry, typically displaying a complete report in just a couple of minutes. This usually details an alarming number of problems (our test PC managed 819) but you don't have to browse through the entire list: just click Repair and Registry Mechanic will remove the redundant entries for you.

The program also provides a Compact Registry to further optimise your system. This works something like a disk defragger, removing gaps and wasted space in the Registry, so it consumes the absolute minimum of memory and hard drive space. The process can take a while, but is definitely worth a try if you'd like to squeeze the maximum performance from your PC.

Registry Mechanic 7 also provides a surprising bonus in its Monitor feature. Leave this running in the background and it'll watch your Registry looking for changes to key entries, such as programs trying to configure themselves to run when Windows starts. It's a handy way to spot spyware, or just discover exactly what an installation program has done, and is yet another reason why you need to install Registry Mechanic right now.

Move to Registry Mechanic 8 and you'll discover new components like the Windows Service tuner, quick access to Windows Manager tools, and an improved interface. Meanwhile a new plug-in architecture makes it easy for further tools to be added in the future. The normal price of a 12 month licence (covering up to 3 computers) is £29.95, but as a registered owner of Registry Mechanic 7 you need only pay £23.96 - that's a 20% discount. Point your browser at www.pctools.com/en/registry-mechanic/free/promo/INCISIVE1208 to order, and check out the other PC Tools programs while you're there. The offer entitles you to 20% off their purchase price, too.