Causes

• Through normal use your computer's registry can gradually become cluttered with unnecessary and even contradictory registry entries. For instance, when you uninstall a program, bits of instructions about the program called registry entries or keys could be left behind.
  
  

Effects

• Since the registry is effectively a list of instructions for the operating system, problems with the registry keys slow your computer because it is forced to sift through the false instructions. These errors can also cause your computer to look for files that no longer exist, which results in system instability.
  
  

Solution

• Fortunately, there are several free, effective programs available online that can help keep your registry in good order. Make sure that whatever program you select allows you to make a backup before making any changes to the registry, in case the attempt to clean causes system instability.