The windows registry is like windows, very complex, and it is also not something for the average user to be messing with.
If your registry needs to be cleaned or repaired, you should not do it manually, always have a piece of software do the job for you. The software tittles available to repair or clean the windows registry are numerous to put it mildly. They all do the same basic thing, scan the registry for dead, broken, erroneous entries. The software will find file extensions that no longer have programs that are associated with them. This is to say that a program you installed told the windows registry that the files it was going to use ended in .xyz or .zxy or what ever they want their files to have. You later un-installed that software package, but the entry in the windows registry that said the program files would end in .xzy or .zxy is still there in the registry taking up room, taking up time to load and generally do you no good at all.
These are the sort of things a Registry fixer/cleaner/optimizer software tittle looks for, and will attempt to repair or delete.
This brings me to my own little rule for working any problem with windows, The rule of three, is my personal rule,. And it states that anything you want to do in windows you should have three different pieces of software to achieve. I have found that no matter how good the software or how many promises they make you, no one piece of software can do the job completely.
This is because of the way the software searches and what the software is searching for, some will not recognize certain errors. So if you have three different pieces of software to do the same thing, and run them one at a time you will be able to find the majority of problems and errors in the windows registry.
After the Software finishes its scan, you should always select repair, this makes the software search for solutions to the problems it has found and if a solution is found the error is automatically fixed.
Some software tittles, most in fact, have an option or present the user with the option of backing up the bad data that it has found before any changes are made, Always select yes and back the data up before doing anything else.
As I already said the windows registry is very complex and even software can find something it thinks is an error when it is not. When you back up before changes are made, you can then tell the software to fix what it can and delete the rest, then if you reboot and your favorite Jukebox software does not work anymore you can go back and tell the windows registry repair software to restore the registry from the back up you made and your system is back to where it was before you cleaned it.
You should run all three of the registry repair/cleaning/fixing software about once a month, or anytime you notice something working slow or throwing errors at you.
Follow this advice and you should have no problem keeping your window registry clean and running smooth.
Thanks for Reading, hope I have been of help.