How to Clean Your Registry

One of the most annoying things on Windows is the registry. It's difficult to understand and gets cluttered with useless bits of information in a matter of days. Luckily, there are free programs out there that can clean out your registry so you don't have to worry about a thing. Of course, if you want to get your hands dirty, you can also try your luck digging into the registry manually and deleting things you know are not needed. This comes at a price: a mistake could be fatal.. for the computer!

Before beginning to the software section, let's check out exactly what the registry is. The registry is a place in Windows that stores all the information about its hardware, software and operating system. It was designed to keep all the configuration files in one place for easy access. From first glance, it seems like someone went overboard because it looks everything but easy! Don't worry, if you know where to look, it's not too hard.

So how is the registry organized? Through "keys" which can hold a value or other keys. You can think of them as folders or a file that holds information (but they're still called keys!). The value is usually a data type; for example, REG_SZ, is a string, which is a "string" of characters, while REG_DWORD is a dword, which is just a fancy way of saying 32 bits, usually reflected in the form of an (unsigned) integer. Knowing these values is not really important; if you knew all of this, you probably wouldn't be reading this article anyway.

So how do we get into the registry? Press start and click run. Type in "regedit" and click ok. This will start up the Registry Editor which allows you to edit any value of any key in the entire registry! Note that there are other methods to edit the registry but this is by far the most used so it will be the only one discussed. From here, you can see all the things discussed above in all its glory.

Ok, so we know what the registry is and how to open up the editor. So how do we clean it? I'm going to give you three ways: two free programs and one very brief tutorial on how to manually clean it

CCleaner:
This free program is highly recommended for just about any computer. Not only can it clean the registry, it can clean out your hard drive, check programs that start on start up (useful to speed up load time) as well as have a very useful uninstaller built right in! You can download it here.

After installing, you'll be able to see four big tabs on the left side of the program labeled "Cleaner", "Registry", "Tools" and "Options". I would stay away from Options as it contains more advanced features and require more specific instructions for different machines and programs. You can learn more about it by searching around the site or reading the help file included. Our focus will be in the Registry tab. Click on it and click on "Scan for Issues". After that, select all the problems and click "Fix selected issues...". This will automatically removed the invalid/corrupted/bad/whatever key from the registry. Under very rare circumstances, this may delete a key that was important. I've never had this happen to me and I've been using it for years but under the unlikely condition that this happens, it's safer to back up the registry. CCleaner has an option to do this but I would rather use the next program.

RegSeeker:
This is the program I use exclusively to clean up the registry (with CCleaner more for hard drive). This is because this program is much more effective at finding problems and cleaning it. This basically means it finds more problems which yields a faster machine! You can download it here.

Note that this program does not install into windows; instead, it's just an executable so store it somewhere safe and have a shortcut created on the desktop for easy access.

After running RegSeeker, you'll see many options on the left. The one's we'll focus on are "Installed applications"->"Invalid Add/Remove Entries", "Clean the Registry" and "Backups". The first thing you should always do is back up the registry and your personal files just in case the worst happens. Actually, you should be doing that anyway because computer's can always suddenly stop working! So if you haven't already, back up your files and registry!

Now to start cleaning using this program, we'll start with "Installed applications". Click on it and click "Invalid Add/Remove Entries". This will remove all the useless entries that may have been corrupted in the add/remove menu of windows. Note that these are actually located inside the registry so you're definitely cleaning the right place. Now for the super easy part: go to Clean the Registry. Select all the options except ones that are marked "experimental" (unless you're feeling brave!) and click OK! It'll automatically scan the entire registry and mark invalid/corrupt/dead keys. This can take awhile so be patient. Then click "Select"->"Select All". This will select everything; then go to "Action"->"Delete selected items" which will clear everything out!

With these two programs working side by side, you'll clean out a lot of junk that you won't catch manually. However, they won't catch things you can find easily manually so it's good to know some methods of manual cleaning.

Manual cleaning:
Warning: these instructions were done on Windows XP. If you are not running Windows XP, I cannot guarantee these keys are the correct keys nor can I guarantee that the names mentioned here match the same name in a different operating system.

Before we begin, go to the add/remove menu in Windows. This can be accessed by CCleaner or through the Control Panel.

Make a note of what programs you have installed and, if possible, who developed those programs. Remember, if you have a program you no longer need, it's best to remove it and save some space!

Writing this down helps but if you have good memory or are familiar with your own programs, you can start cleaning the registry.

To do this, we'll have to start up the Windows Registry Editor. Do this by clicking Start->Run and typing in "regedit" and pressing ok.

On the left side, we can see a whole bunch of folders (keys). The main part we'll focus on is HKEY_CURRENT_USER. If, however, you're the only user on Windows, you can do the same for HKEY_LOCAL_MACHINE.

Click on HKEY_CURRENT_USER and find the Software folder and click on it.

You should now see a lot of folders with names of the developer that made many programs installed on your computer. Some common ones you'll find are Adobe (for Adobe Reader) or Apple Computer, Inc. (for iTunes).

Remember those developers you saw (or more importantly, didn't see) in the add/remove menu? If you see them in this list and you know the program they developed is not actually on the computer, it's probably safe to delete that entire folder. I say probably because there is no guarantee here.

However, you can somewhat check if it's a valid key or not by looking into it. If the entire key contains values that say "(value not set)" and the key itself is of a developer not within your add/remove menu, then it's probably safe to delete. In fact, under those circumstances, I would delete the registry. Once again, I cannot guarantee the safety of Windows if a mistake is made!

Note that, similarly, if you see a key you don't recognize but it contains values, it doesn't mean you can't delete it. In fact, that's one of the dangers in using the Registry Editor, you can delete it. So watch out for those! If you really don't know what the key stands for, simply do a search on Google and see if it comes up with a program that is installed on your computer.

A final word, if you're the only user on Windows, then you can also do the same for the keys in HKEY_LOCAL_MACHINE. This is because the keys are often overlapped in terms of what it contains. However, if you're not the only user, I recommend against messing with it as it could contain valuable information for other users!

These instructions is the most basic method of cleaning the registry; something more advanced can be found somewhere online but I would not recommend those anytime soon as they could seriously damage your computer to the point that you must reinstall Windows.
Good luck in cleaning Windows and its registry and remember, back up often!