Once the maker of one of the best PC cleaning and optimization tools on the market, Iolo Technologies had slipped a bit in recent years, turning out mediocre versions of its flagship System Mechanic software. We're happy to see that System Mechanic 6 is substantially better than the two prior versions.

System Mechanic's original appeal was its promise to make your system run quicker and leaner, with simple, easy-to-use tools. This version answers that promise with an informative interface. Most striking about the shipping version we tested are the colourful audio-volume-style meters that display your computer's overall health and security status at a glance. We also appreciated the applications logical layout, which should provide novices with fast access to the most important tools for cleaning out junk files, optimizing the Registry, speeding Windows' startup, repairing hard-drive problems, and killing spyware. Drilling down to the more expert tools is intuitive, though most people will probably never get around to them. The basic tools are that good. Below the meters is a box with six items detailing where your machine is in good, or bad, shape. The first four -- Clutter, Speed, Safety, and Fitness -- tell you which major repair tools you should run to optimize your system. The two other items are for maintenance: Update indicates whether System Mechanic is fully updated, while Active Care lets you know whether an automated maintenance schedule has been set up.

You can run repair tools directly from within this box or use the Power Tools buttons on the right side of the application's interface.

The first of these buttons is the all-in-one PC TotalCare tool. This is a good place to start if your machine has a lot of problems, because the tool runs all the most important repair and optimization applications with a single mouse click. However, it is extremely slow; painfully so. We jumped immediately to the PC Cleanup tool which quickly found -- and eliminated -- a gigabyte's worth of Windows temporary files, cookies, and cached Web pages.

The PC Accelerator tool is my favorite part of System Mechanic 6. This tool optimises your Internet connection settings, removes any unnecessary programs that crank up when Windows starts, defragments your hard drives and system memory, and compacts the Windows Registry. We used the last major tool, PC Repair, to fix broken shortcuts and to delete spyware apps and invalid uninstallers. After we used the tool, System Mechanic declared our PC in tip-top shape, but shortly thereafter a system-tray icon reported that my machine's health and performance could stand improvement. However, when we restarted System Mechanic, it found no problems to fix.

Beyond this modest issue, we didn't run into any problems, which leads me to recommend System Mechanic 6 as a fine addition to any PC optimisation arsenal.