Ever wonder why your computer feels slower than the first time you use it. Well, you might be right to feel so. This is because the longer you use a computer (running a copy of windows) you accumulate temporary files, Internet Browsing history, Registry Etc. So once you start using CCleaner, your computer should be as good as new. :)
Now, there are alot of software that might suffice your needs, but i am suggesting CCleaner to do the job. The reason for my suggestion is that CCleaner is a free ware and the interface is pretty easy to understand. And also, the cleaning job is exceptional. Try it out.