Lots of programs build up their own history, cache and temporary files taking up HDD space and slowing down your system. Cleaning all of your applications one by one is time consuming, but there are programs that can scrub your programs in one go.
History Killer is designed to do this quickly and simply. It features a list of common targets, like Windows System, Internet Explorer and other browsers, accessories and Microsoft Office. first you scan the targets, then you can chooses individually whether you want to delete everything or not. It's really clear and easy to understand.
What you can't do is add programs to the list History Killer offers - while this may be fine for some users, most probably use something that's not listed. It's an effective but very basic application, and there are programs like CCleaner will do the same and more besides with no more effort.
If you use the basic set of applications that History Killer lists, this is a fast and easy way of clearing their histories, but it's not very flexible.