1) CCleaner (Free)
CCleaner can be used as a tool to delete temporary files and other unused files on your computer, by deleting these files you can free up tons on space on your hard drive and make your computer faster at the same time. This program also has other capabilities like registry cleaning. When programs are uninstalled not all the files associated to them are deleted, what the registry cleaner does is it deletes the unused entries in the registry thus making your computer faster and your registry less clogged. These are only some of the features of this brilliant program to see all the features please visit their website.