Permanant Deletion of internet history

Hi,till now I have been deleting the history of sites I visited by the traditional way(in IE,Tools->Internet Options->Delete Cookies & Clear History.But my friends told me that any Computer genius may easily know which sites I had been visiting through Windows registry.Can any of you tell me which is the way to see the internet history(even if it was cleared in the popular clear history method) through Windows registry & what is the way to delete the internet permanantly.Is there any fee software avilable for this purpose?