If this worked with no ulterior motives, this might have been helpful back in the good ol' windows XP days. Operating Systems have come a long way since then, and done away with the needs of things like defrags and optimization software. Have something for spyware, anti-p2p, viruses, and firewall and you're good.
CCleaner is good for freeing up space and removing temporary files you don't need any more, and gives a nice warm feeling when you use it. You aren't going to notice a speedup though.