If you decide to use a registry cleaner, make sure you choose one that's reliable and safe. Here are some excellent options.
Along with viruses and malware, the registry is the Achilles Heel of Windows. From within that hierarchical database, the operating system can be rendered unbootable, slow, or problematic. So it behooves the admin (or the user) to keep the registry as clear of errors as possible.
Here's the problem. With rampant and careless software installation, the registry gets mucked up quickly. And when the registry gets mucked up, bad things happen. Aside from being fastidious with your software management, you can use various tools to help keep the registry clean and free from errors. There are tons of registry cleaners out there, some of which do what they promise. Others are snake oil or worse. Here are a few apps you can trust to handle the job and keep your registry as clean as possible (without manually running a fine comb through every entry).
CCleaner is my go-to cleaner. I know it gets a lot of flack for having to be run multiple times (to fully clean the registry), but it always does the job, and never have I seen CCleaner render a system unbootable or worse for wear. One of the things I like most about CCleaner (aside from the fact that it will also rid your machine of temporary Internet files) is that it will always prompt you to back up your registry before you run the cleaning tool. CCleaner is also a mid-level cleaner, in that it does not go too deeply into the registry, so you don't run the risk of breaking your machine.
2: Comodo System Utilities
Comodo System Utilities is another product with more features than just registry cleaning. This tool will dig a bit deeper than CCleaner but is just as safe. Comodo is one of those companies that's not nearly as well known as it should be. Its products are always topnotch and affordable. The System Utilities tool is free, so you can't go wrong. This registry cleaner should be considered more of a deep cleaner. Once you've run it, you should experience a much-improved system. And like CCleaner, I've never seen Comodo System Utilities brick a PC.
3: TweakNow RegCleaner
TweakNow RegCleaner works with Windows XP, Vista, and 7 and does a fantastic job of removing obsolete registry entries. Although not as deep a cleaner as Comodo, TweakNow RegCleaner is one of the fastest registry cleaners you will ever use. If you're looking for a mid-level cleaner and speed is the name of the game, TweakNow is what you want. TweakNow RegCleaner will also clean up traces from Web browsing, clean Windows temporary files, compact Google Chrome and Firefox database files, optimize Windows settings, and optimize network settings.
4: Wise Registry Cleaner Free
Wise Registry Cleaner Free offers a unique restore feature that most other registry cleaners don't have. With this feature, you can restore back to the previous registry state with the click of a button. Wise Registry Cleaner also offers registry defrag, scheduling of tasks, registry backup, and free technical support. Of all the free registry cleaners, Wise Registry Cleaner Free should be considered the Mac Daddy of them all. One nifty feature: If you double-click a registry entry (after scanning), Wise Registry Cleaner will open that entry up in the Registry Editor, where you can manually edit or delete it.
5: AML Registry Cleaner
AML Registry Cleaner is more of a power-user registry cleaner (though not to the level of manual editing) and offers added features, like keyword search, the ability to add your own junk file removal, and the ability to see all startup applications. AML Registry Cleaner finds quite a lot more keys for removal than most other cleaners. This, of course, can be considered both good and bad. For me, this is one of those tools I use when low- and mid-level cleaners can't find junk entries causing problems with the registry. But beware: With the power this tool offers, you can run the risk of breaking the registry. So as you would do with all registry cleaners... back up your registry before you do anything to it or with it!
There are plenty more registry cleaners available. But these are the tools I used more often than not and they've always been a huge help in getting a system running in a much faster, more reliable state. Do you have a go-to registry cleaner not mentioned here? If so, what is it and why do you prefer it?