The software scene is crowded with Registry editors and cleaners, each promising to improve your system's performance and enhance your online security by deleting old, broken, invalid, and downright dangerous entries in the Windows Registry as well as cleaning your disk drives, browser caches, and other stores of sensitive information. They typically offer a free download version that will analyze your system and uncover rows and rows of malicious-looking items, which of course you want to delete because they look so threatening, highlighted in red. However, to actually clean or tweak your system, you must fork over 30 bucks for a full version, which you do because you assume the software knows more about it than you do. After you run the cleaner, you find that some Windows features no longer work, or you can't open this or that program, or your machine won't even boot because the Registry cleaner has deleted critical files.
That's the state of affairs with Macecraft's jv16 PowerTools 2009, a suite of tools that not only cleans and tweaks the Registry but also lets you disable Windows features that you don't need or never use, delete sensitive personal data, and so on. Like similar products, it can do a good job, if you are careful how you use it.
The free version of jv16 PowerTools is limited to a 30-day trial, after which it's $29.95 to buy. There's also a freeware version, PowerTools Lite, with fewer features. As with all such utilities, use PowerTools with caution.