Russ,

Cleanning the registry with CCleaner has cured a problem I had with my system. However, Uncheck applications and application paths, which when lefted checked has caused me problems.

Richard, Richard, CCleaner is no longer the way it used to be, that's why I no longer use that cleaner! Then I speak about 7 years ago! I usually use PrivaZer!

Russ, if you install a programme and later remove it, sometimes the registry will still contain part of that installation. You are right that is no problem.
But if you reinstall that programme, or an update, those old registry entries could provide a problem. Many times, this site will giveaway updates of an earlier giveaway. I often read here that there are users that have a problem with these obsolete registry entries. So, cleaning the registry before installing new software can be advisable.

"Registry enteries [sic] are an essential part of your system...

True

"and if messed about with can brick your machine."

Generally Only If deleting driver-related entries or if one of the hives becomes corrupted.

"There is absolutely no need to "clean" the registry files as they are very small and damaged and obsolite enteries [sic] are ignored by the operating system."

If you consider anything under 2GB small, then yes, the registry hives don't take up much space. All registry entries are read without qualification -- there is no obsolete as far as Windows is concerned.

"Even after cleaning your resistry [sic] it won't improve your computer's speed and make it run better."

Maybe -- maybe not... only way to find out is to perform a backup that you can restore & try it. Too many people have previously reported benefits in GOTD comments to dismiss registry cleaners as useless.

"Registry cleaners can be dangerous and editing or modifying the registry should only be done by advanced/expert users"

Registry cleaners can delete known garbage, but otherwise delete entries with orphaned links. That *Should Be* harmless... however, an app may be in its umpteenth generation, reusing old code that checks for certain registry entries, even though they're currently useless, so if you remove them that app breaks. That's why you should perform a backup first -- if there's a problem you can put everything back, so the only danger is that you might lose the time it takes to restore a backup, which might be as little as 10 minutes. Macrium Reflect Free is free, anyone can use it -- no expert qualifications needed -- and you can pick up a small SSD & an external housing for it [to store your backup] for ~$25 on sale.

Colin Martin, Agreed. I was a paid user of CCleaner. Got too big for their virtual britches. Thanks Ashampoo!