You can image that when you are either installing or uninstalling a program or hardware when windows mistakes occur and then changes happen in your windows registry that may not always be accurately reflected, so creating countless unused applications, unfinished commands, and broken drives.  As everyone knows that windows registry is a very crucial database in which all programs that you use, including Windows itself, store a great volume of info.

Once you notice that your computer is acting a little lethargic or slower than normal then you should definitely test your registry for errors.  The very first thing you have to do before checking your registry would be to discover what is causing the blunder.  Run your antivirus to test for rogue files.  If the scan comes up clean but your PC is still slow then you can move on to doing a registry scan.  There are many free registry scanning tools that you can run on your PC wherever you could be.  This would help disclose the errors in your registry as well as eliminate all of the new, invalid and bad info that has been saved there.  Remember, it isn’t. For help on how to fix Windows errors go to Windows XP Errors.