Have you tried running CCleaner it does get rid of a lot of junk that is not needed.I run it about once a fortnight to help keep mine clean and to help it run a lot faster. It may take awhile the first time.Click on the windows and then where it says run cleaner. When that as done click Application and then click run cleaner
Will put a link belowe just run the free version.
http://filehippo.com/download_ccleaner/