Crap Cleaner or Ccleaner is an excellent free registry cleaning tool, that also clears out crap and temporary files etc...
www.ccleaner.com/
Also, Pirisoft Defraggler, although in Beta stages this defragmenting tool is excellent, it has the option to defragment files individually (i.e. the fragmented files only) or the whole drive, (which speeds everything up).
Also removes fraggles... I think... (if they even exist...)
www.defraggler.com/