Registry First Aid
Registry First Aid is eager to help you fix and compact your Registry--and it does a terrific job at it, too. Of all the programs I tried, this one inspired the most confidence, both from a safety perspective and in the way it handled Registry problems. The interface is clean and easy to navigate, and the program includes a Registry Defragger, a Registry searching tool, and a built-in, automatic backup module. Registry First Aid supports all versions of Windows.
The only downside is that the program costs $28; the trial lets you see everything the program does, and is fully diagnostic, but only fixes 14 entries at a time. I'm hoping that won't dissuade you from trying the Registry First Aid.
Registry First Aid found 2161 faulty entries in a scan--a thorough one at that--which took about 20 minutes. I was comfortable with the way the problems were listed: Either by category--such as invalid file or DLL, invalid path, or unused software entries--or by safety level. All the entry issues that were safe to fix were automatically check marked and I liked having to manually check those listed with "caution," or "extreme caution."
Most problems First Aid found were marked with "delete the entry," but some had other choices. I could cut the invalid substring or, in some cases, repair the entry. Unfortunately, the program's Help wasn't too helpful, so I opted to use the default.
While the program was scanning, I was able to examine each listing, check or uncheck it, or open the specific entry in the Registry. It made sense being able to view the errors by category or by safety level; filtering was handy if I wanted to find a problem about a certain program or issue.
A super feature--and one worth the price of admission: with one click, most of the problem entries popped open my browser and had Google search on the Registry key. Very cool and ideal for determining if a risky entry should be removed.
One quibble: I wasn't happy that the tool wanted to find a home in my System tray, unnecessarily adding clutter just to check for new versions. I disabled it in settings.