How to Speed up your Computer - Part Five: Clean the Registry

This is Part Five of a five part series about how to speed up your computer.   Here are the other four posts.  Before you follow these suggestions, however, you should get rid of your malware.  Here are the instructions.
The registry is a listing of all the settings and options in Windows. They are listed in the form of “keys”. When the registry gets cluttered with unfunctional and useless keys the computer still has to refer to them and this slows the processes of booting, running applications and going on-line. To fix this, you can delete or edit the keys manually which is tedious and risky, since changing the registry is a good way of messing up the computer completely, if you don’t know what you’re doing.