Recently I have been trying to suss out what the Windoze Registry does. I have solid non-microsloth "Mirror" backups so I can trash anything and be able to restore my system to EXACTLY what I had before.
One of the first things I did was to use UNINSTALL to take programmes off the system. One of these was RealPlayer. When I checked through the registry all the references for RealPlayer were still there. It does not seem to remove all the junk that it puts on the system.

As for the Registry - WHAT A SHAMBLES of a system! It is the computing equivalent of taking everything you need to run your business and just throwing it into a pitch black cellar.
It is full of files with untraceable names which, unless you can find and decipher an "installer" script somewhere on your computer, you cannot identify which have been installed by what programme.
At least with the old Windows3.1 you could actually find an "*.ini" text file which belonged to installed programme and contained your chosen settings for said prog.

Of course, that is what the spyware and virus bods rely upon, and the fact that it is such a joke that you have very little chance of ever finding and removing unnecessary information unless you dedicate your life to being a computer geek, unlike most of us who just wish to use it as a tool to do what we actually want to do.

Quack!
GtD.