The reason that duplicate system files slow down a PC as much as they do is pretty straightforward. The multiple copies of the same music file, photo, or other system file clog up your hard drive and rob you of free space, which in turn puts stress on your hardware and slows down your operating system. Frequently if you’ve upgraded to Windows Vista or Windows 7 from a previous version of Windows, you may find multiple duplicate files that you no longer need.
To get rid of remove duplicates on windows, you can either use your own intuition and the search feature, or you can use software that makes the entire process easy. I prefer software, because I don’t have endless time to search my system folders by hand. A good piece of software will use a byte-comparison method, and will make it simple to delete duplicate mp3s, photos, program files, and more. Any file extension, in fact.