I have used CCcleaner but it doesn't speed up my computer. Slowly over time there are just more and more processes that auto load at boot up. I used to have 1 or 2 svchost.exe running at the same time now I have several. There are many processes I just don't recognize, and used to not show up.
As others have said I make it a habit to reformat and reinstall my OS about every year and a half to two years. Unless you are a gamer or want the latest OS there is usually no reason to upgrade hardware.