CCleaner

Product: CCleaner
Company: Piriform Ltd
Website: www.piriform.com
Type: Free
Requirements: Windows XP/Vista/7

CCleaner is our system optimization, privacy and cleaning tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. Additionally it contains a fully featured registry cleaner. But the best part is that it's fast (normally taking less than a second to run) and contains NO Spyware or Adware!