The Windows Operating system registry is a "place" where the OS (Windows) stores information that it needed for later. This can be a number of different things such as the location of system files needed to keep your computer running, installation paths, what kind of hardware your system has, ports being used, etc. To keep it simple the Registry can be described as the "brain" of the Windows Operating System. Whenever you uninstall an application, sometimes registry entries are left behind, or sometimes applications can store invalid entries, spyware from the web can clog it up, and eventually overtime you have a mess which could cause your computer to drastically slow down. Imagine if your room had clothes, and endless piles of junk scattered around. You have lost your car keys and you know it is somewhere in there, but it will take you a while to sift through the mounds of clothes and other odds and ends. Imagine if your keys were on the floor and you had a clean, organized room. It would take you much less time to find your car keys, because there is no useless junk getting in your way. So we've uncovered another reason why you must keep your registry clean: to keep your PC running fast. We now know why the Windows Registry is important, and how it gets corrupted, but how do we clean it? Going through it manually and deleting entries yourself is HIGHLY discouraged. Deleting something important by mistake, or deleting something that looks unimportant, may cause your computer to come to a devastating crash, that could possibly ruin your entire system. I would recommend purchasing some kind of registry cleaning software, because in my opinion, manual cleaning of the Windows Registry is a complete no-go, even for highly experienced PC users. Once you find your registry cleaning service software of choice, I would recommend giving it a good cleaning at least once a week. I recommend using Registry Easy, it is affordable, easy to use and they offer a free scan for first time users. So if you've been wondering why your PC has not been running like it used to, or if unexpected errors keep coming up more frequently, consider spending the little extra cash to clean your system before you find yourself spending a lot of extra cash replacing it.