CCleaner is a system optimization, privacy and cleaning tool for Windows 98 to Vista. The system is freeware, although they do deserve a donation if you are going to use the software for commercial purposes. This cleaner allows your system to run faster, without the clutter that gathers on all Windows systems over time. It also has a good registry cleaner, to remove all of those registry entries that are no longer needed. To give you an idea, when I ran it on my Windows system (which is 2 months old) it freed up 1.705Gb of disk space, and cleared 94 registry issues. To date they have had 350 million downloads of the software. This is a great tool for the IT staff to keep on their utility memory sticks.