How to Clean a Corrupted Windows Registry

A computer free of errors runs smoothly, with the probability of crashing dramatically lowered.  However, over time and continuous use, it develops errors, especially after a number of run-ins with malicious software, like virtses and spy ware.  The computer may end up having a corrupted Windows registry, which leads to the dreaded computer crash.  By cleaning up the registry, you can protect your files and ultimately, your computer.
Back Up Your Files
Before cleaning the computer's registry, see to it that you have backed up your files.  An error in cleaning could easily wipe out your files.  Save your computer's contents on a different drive and/or on an external hard drive.  That way, you can still recover your files, even if you screw up the registry cleaning process.  After backing up your files, close all active programs, since they can interfere with the cleaning.
Registry Cleaning Software
Cleaning the registry, manually is quite tedious, which is why many people rely on registry cleaning software.  These programs are available on computer software stores or can be downloaded through download sites like http://www.download.com or through Bit Torrent.  Do some research on the product before downloading, since some of them may not be as efficient as advertised.  Once you have one installed, just follow as directed by the program.  In an hour or two, your computer should be running smoothly.
Manual Cleaning
 In some cases, the computer won't open up Windows, which renders some registry cleaning programs useless.  You have no other choice but clean the registry, manually.  Here's how:
1.    Slip the Windows XP CD in your CD drive then reboot the computer.
2.    Press "R" when the option appears, opening up the Recovery Console.
3.    Choose your preferred means of installing Windows, then supply the administrator password, if your computer was assigned one.  You'll then be taken to the command prompt, which comes as a black screen with a blinking cursor.
4.    Enter the following data:
md tmp
copy c:\windows\system32\config\system c:\windows\tmp\system.bak
copy c:\windows\system32\config\software c:\windows\tmp\software.bak
copy c:\windows\system32\config\sam c:\windows\tmp\sam.bak
copy c:\windows\system32\config\security c:\windows\tmp\security.bak
copy c:\windows\system32\config\default c:\windows\tmp\default.bak
delete c:\windows\system32\config\system
delete c:\windows\system32\config\software
delete c:\windows\system32\config\sam
delete c:\windows\system32\config\security
delete c:\windows\system32\config\default
copy c:\windows\repair\system c:\windows\system32\config\system
copy c:\windows\repair\software c:\windows\system32\config\software
copy c:\windows\repair\sam c:\windows\system32\config\sam
copy c:\windows\repair\security c:\windows\system32\config\security
copy c:\windows\repair\default c:\windows\system32\config\default
5.    Type "exit" after.
6.    When your computer is booting up, press F8 then choose Safe Mode.
7.     Log in as the administrator then activate System Restore (Start - Search - Search for System Restore).
8.    Set a restore point, so your current settings are saved.
9.    Copy the following files to C:\Windows\Tmp:
 _REGISTRY_USER_.DEFAULT
_REGISTRY_MACHINE_SECURITY
_REGISTRY_MACHINE_SOFTWARE
_REGISTRY_MACHINE_SYSTEM
_REGISTRY_MACHINE_SAM
10.    Once done, rename the files you just inputted, based on the last word of their file names. For example, _REGISTRY_USER_.DEFAULT should be renamed to DEFAULT and so forth.
11.    Repeat steps 2 and 3.
12.    Enter the following commands on the command prompt:
 del c:\windows\system32\config\sam
del c:\windows\system32\config\security
del c:\windows\system32\config\software
del c:\windows\system32\config\default
del c:\windows\system32\config\system
copy c:\windows\tmp\software c:\windows\system32\config\software
copy c:\windows\tmp\system c:\windows\system32\config\system
copy c:\windows\tmp\sam c:\windows\system32\config\sam
copy c:\windows\tmp\security c:\windows\system32\config\security
copy c:\windows\tmp\default c:\windows\system32\config\default
13.    Repeat step 5.
14.    Once your computer boots up, repeat steps 7 and 8.
Cleaning windows, as you can see, is quite tedious.  If you're not adept at navigating and tweaking Windows, you might as well have a programmer or a computer technician perform the task.  You won't pay much, since the job is elementary for them anyway.

To learn much more about fixing windows registry problems [http://www.allaboutwindowsregistry.com/software/windows-registry-cleaner-removes-the-outdated-entries/], visit AllAboutWindowsRegistry.com where you'll find this and much more, including how to clean a windows registry and fixing windows registry issues.