You may want to read the information at this link:
Windows Registry Information
http://www.bluecollarpc.net/registry.html
To begin .... The difficulty in spelling out how to work with the Registry and associated Files is not easy and only for one reason. That reason is that mistaken deletions will cause damage. This is why it takes time - even months - to begin to know your machine like the back of your hand, what's under the hood. A healthy fear is necessary to learn. However, the bottom line is that this eventually becomes necessary for all computer owners unless you are rich enough to keep dropping your Computer off at the repair shop for what you will learn are very simple procedures as easy as deleting read emails.
You begin by location - how the location of Files are written and how the location of a Registry key is written. The location written shows where it is at on the computer. This becomes essential in communicating that for help and also identification of a malware file or registry entry. In learning this, you will eventually be able to manually inspect your computer from time to time for malware as well - beyond simply blindly trusting security software that admittedly is not 100 percent effective. Eventually, through trial and error and repetition of visually identifying locations, you also learn the areas malware installs on the computer and this in turn makes you that familiar to 'take a look under the hood' and manually inspect your machine for malware entries. You may find inert inactive fragments or remnants of a spyware or adware installation that was removed previously. You may blunder onto a variant of a malware that was as yet undiscovered and make a report of that to antispyware companies at their websites - simply by recognizing the familiar files and registry entries of a previously removed installation from memory of it. This can occur during a registry cleaner scan as well - an item presented that turned out to be one of these. You can also report any left over item the antispyware program did not remove, and they will add that to current definitions.... but you must know location and how to write that. In the Windows Registry you can right click a key and click "Copy this Key Location" and then paste that in a text file or email. This is another way of seeing how the location is properly written and how that is pointing to it.
Unless you know what you are looking at DO NOT DARE DELETE ANYTHING IN THE WINDOWS REGISTRY OR YOUR WINDOWS OPERATING SYSTEM AND / OR OTHER SOFTWARE WILL BE RENDERED INOPERABLE... is the only way to say that.
Okay, let's take that look under the hood. The Windows Registry - how to get there?
Click > Start (lower left) > and click Run (on the menu) > and type in " regedit " in the little box. This automatically opens the Windows Registry.
On the left tree you click the little plus signs ( + ) that spread or collapse the tree. Collapse all the trees to the five sectors -
HKEY_CLASSES_ROOT
HKEY_CURRENT_USER
HKEY_LOCAL_MACHINE
HKEY_USERS
HKEY_CURRENT_CONFIG
Now spread the HKEY_LOCAL_MACHINE key directory open. Skim down and spread open "Software". Notice all the names of Folders of your software. These should be very, very recognizable to you by name.
Okay .... shut the Registry (you can return anytime). To close it just click the " X " (means close file) all the way uppermost top right corner.
Well now you've been inside the Windows Registry without touching anything. The area we were looking at is one of the most common places registry items are deleted from and I will show you why....
Now we are going to look at the Files these keys are all associated to - the software and system that entered them.
Right Click > Start (lower left) > on menu click Explore... this will automatically open Windows Explorer were all your Software Files and the Windows Operating System Files are at... Local Disk (C;) - the "C-Disk".
Spread open the tree on the Left (the same manner of clicking once the little ( + ) plus sign)...
+My Computer to
+ Local Disk (C (The C Disk)
and spread open C Disk (where all files are on)....
Skim (scroll) down to "Program Files" and spread that open. Hover on or highlight on "Program Files" on the left and tap or click that just once. Look in the right side. All the Program Files folders will appear and have their names on them. These, again, will be very recognizable by software name. These are the actual Software Program Files (inside the folders) and don't touch them. (Any change there can corrupt the software programs - they must remain unchanged).
You will notice on the left side - spread open the Program Files tree spread and you will see on the tree every sub folder (directory) of Program Files you are looking at on the right for your installed software. Each software has its own Folder that occurs automatically when you click "Install".
Now if you remember, over in Windows Registry these look very, very similar. Generally when you uninstall a software - whatever is left over (not removed) then is called an "orphan" meaning a file or key without a parent folder - here the Program Files folder - although many times the empty Program Files Folder is still there after an uninstallation. When you uninstall a software - the left over corresponding registry items are then instantly picked up in a registry cleaner scan as safe to delete because this software no longer exists obviously.
Now this is where quality comes in. Most registry cleaners are not worth 2 cents unfortunately as they find too many "false positives" - meaning they are detecting registry items that belong to valid programs installed and running on the computer. This is another reason you NEVER click Delete in a Registry Cleaner or 'Move to Back Up Folder' unless you have positively identified it as safe to delete. This is another reason I slam Spybot Search and Destroy which used to present registry items for deletion and is why actually in most circles it is deemed for advance use only, though all newbies are directed to use it by uninformed persons who preach to have blind faith with it. This you NEVER do when it comes to your Registry. Most times System Restore will replace Files deleted but many times it can not replace Registry items deleted. This mistake generally takes some Disaster Recovery program by the experienced, and may be possible to re-write deletions back into the Registry by the trained and experienced. Now you know why just ONE mistake in the Registry IS a disaster. Depending on what and where it was, Windows may not be able to operate properly again. The software certainly won't and will cause the computer disk most likely to indefinitely freeze up or even constantly crash the computer altogether until fixed. If it was actually the fatal mistake of deleting part of the Windows Operating System, the cheapest way out would be to simply purchase a new Windows copy and start from scratch - because most likely it will never boot again until then - or in other words it would cost up to 3 and 4 and 5 times as much as a new license copy to drop it off at the Computer Repair Shop.
You must become very, very familiar by going back and forth manually and looking at both sides and are totally positive that a registry key you are going to delete is indeed some left over fragment of an uninstalled software.
If you are using a registry cleaner that does not allow you to double click an item after a scan and it automatically opens right to it in the Windows Registry highlighted - DUMP IT.... it is a piece of crap (feature-wise) and you don't want to trust the idiot that made that treating you like an idiot unable to make an informed decision of deletions. (The old "trust your computer to no one but yourself, and you only have yourself to blame for it").
If it does not give you the full location listed in the results of each item - DUMP IT - it is a piece of crap (feature-wise) and you don't want to trust the idiot who made it who is treating you - the informed public - like an idiot. A 30 dollar loss is better than $3,000.00 !!!! worth of computer you can't use if you spent it already for an inferior product.
For now as a beginner, I would get familiar with things first and just do a lot of dry runs.... do the registry
scan after certain events and look over the results. See what shows up all of a sudden after uninstalls. You should begin to see a pattern and become that familiar with normal deletion operations that are safe. There is NO HURRY to delete anything. You can let the trash pile up a long time before you have to put it out.
The other thing that is going to help is learning to properly writing the Location of an item in Files and then in Registry - and learning how to locate them when you see this.
Example : Adobe
The Files location is written like this:
C:\ProgramFiles\Adobe ....
which means to go to Windows Explorer and on Local C Disk at Program Files - there, Adobe is a sub folder.
The main Registry Key looks like this:
HKEY_LOCAL_MACHINE\SOFTWARE\Adobe....
Which means open the Windows Registry to Local Machine and in Software - Adobe is a sub key.
So Bottom Line is that you MUST locate each and EVERY registry item presented to you for deletion and inspect that. Is it truly a left over orphan belonging to nothing ? Is it in the location expected for this ? Until you can answer that like your life depended on it and you are actually that confident - YOU NEVER DELETE ANYTHING IN THE WINDOWS REGISTRY UNLESS YOU ARE ABSOLUTELY SURE.
The bottom line here is that I am passing on the general knowledge learned that brings any Computer Operator from novice to Advanced User. The chain goes for operators (users) like this universally: Novice (newbie) > Intermediate > Savvy > Advanced > Professional > Expert.
....So these lessons here, hopefully, should be enough to bring you up to Intermediate User at least, knowing and identifying Files and Registry entries in your computer - where to find them, and how locations are written and found - easily and effortlessly.
I hope this helped more than answers that may have hurt !