The registry is a large database in the Windows system, which contain all kinds of program data, system settings, and so on. After long time usage, the registry can get corrupted and lots of useless entries can slow your computer. Good thing, there are means for you to clean your Computer's registry and correct the problems in it.

1. How To Fix Your Computer Registry
http://www.youtube.com/watch?v=I-ZW97AyeYg
source: http://www.wikihow.com/Fix-your-Computer-Registry-for-Free

2. The registry is a huge database
in the Windows system,
containing all sorts of program
data, system settings, etc. After
long time usage, the registry
gets messy and a lot of useless
entries can slow down your
computer.
Automated Cleaning
1. Research registry cleaner
programs. There are a lot of
different programs available
online; read up on tech review sites to find one that will work for you and that has
good reviews from other users. Many of these programs cost a fee, so if you are
trying to fix your registry for free, make sure that you find one that does not cost
money.
2. Download a registry scanner program. Some of the many are listed below in the
sources and citations.
3. Go through the program you chose and see if there is an option to automatically
scan and fix the registry on a schedule.
4. Close down all open programs other than the registry cleaner you have
downloaded.
5. Run your registry cleaner program. You should still use extreme caution even
when using an automatic registry-cleaning program. Many programs will give you
the option of approving the deletions that they want to make; it is recommended
that you use one of these programs, rather than one that deletes automatically.
Only delete those files that the program thinks are absolutely safe to delete; if
you delete recklessly, you could remove files that impair the ability of your other
programs to function. Make sure that you follow all directions provided by the
program, and if you are unsure whether a file is OK to be deleted, it is best to
leave it.
6. Upon completion, close the registry cleaner program. Hopefully, you will notice
an improvement in the speed of your computer.
source: http://www.wikihow.com/Fix-your-Computer-Registry-for-Free

3. 7. This method is recommended for the average Windows user, since the registry is
difficult to understand and fiddling with it can have very bad results for your
computer.
Manual Cleaning
8. Go to the start menu.
9. Click "Run."
10. Type in the name of the registry editing program, regedit.exe.
11. Once you have run the regedit.exe program, you will have access to your
registry's files. From there, you can look through your registry and select files for
deletion. Keep in mind that the registry can be very hard to navigate. The names
of files do not always give you a clear idea of what they actually are. Deleting
registry files without knowing what they are can be extremely harmful to your
computer.
12. This method is probably not the right choice for the average computer user, as
the registry is very large and complex.
To check out a tool for fixing your Computer Registry, click here.
source: http://www.wikihow.com/Fix-your-Computer-Registry-for-Free