What happens over time is you install programs, then eventually uninstall them continuously. But uninstallations don't necessarily remove all traces of the program. It may still leave traces in the registry. The registry is a giant library that holds key details of all programs you installed as well as info for the operating system itself to use. This giant library has to load before you see the window gui (the homescreen ). Disk defragging will help organize the registry so calls to your hdd or ssd (harddrive) are quicker. also a free program called CCleaner can help with some of the unnecessary registry items in your registry. In short use CCleaner to clean your computer of unessary files and disk Defrag.
