Delete the traces of your navigation on the Internet

[Overnight]

Select "Internet Options" from control panel. In "History of navigation" section, just click on "Delete..." and choose the elements you want to make disappear.
You can also delete these ones directly through Windows explorer.
For each user_profile, empty the files in folder "c:\documents and settings\user_profile\local settings\temporary internet files" (note that "local settings" is a hidden folder).
Another way to delete these files but also the last documents you have opened and the last programs you have executed is to use the "Delete" button in taskbar's
customization properties.