It has been said many a time that Registry cleaners do nothing to increase your PC speed. They are such a waste of time as well as money and still they lure many helpless users into using them, unaware of their true side.
In the case of Windows registry, you will find that it contains a huge amount of settings which have been left behind by Windows as well as the huge list of softwares and programs that have been installed. Thing important thing is that even after you have uninstalled a program, your registry may not be cleaned by the uninstalled program for its files. Hence there will always be something left behind even after you have uninstalled something.
The fact is that even if a lot of files have been removed, say 1000, it will not bring any considerable change in the speed of your system. Another important thing is that your computer is not lacking for space and you do have considerable amount of free space left. So bothering about your hard drive is actually pointless.
Well all these do not mean that having a registry cleaner is outright useless. In some rare cases, we have witnessed some level of increase in the speed of the system but you have to understand the specific reasons for such a considerable increase in speed. It was not because of any magic from the cleaner but it is because the program actually had left behind an invalid context menu.
Even then, such incidents are very rare and you do not have to run a cleaner in case you have one, many times a day as it is actually quite pointless in doing so.
Other than investing in registry cleaners, you could on the other hand take a little care about what you install and this will improve your system speed to a great extend beyond a doubt.