Washington Post
"Make sure you download the portable version of Piriform's Registry cleaner and repair tool. Aside from finding and deleting broken items in the Windows Registry, it cleans out bits of Internet Explorer that can compromise your privacy (such as the cache and cookies), deletes chkdsk file fragments, manages restore points, and does an assortment of other tasks."

Read the full review at:
http://www.washingtonpost.com/wp-dyn/content/article/2009/12/07/AR2009120702304.html