portable registry cleaner

FCleaner Windows Cleaner

FCleaner is a Free and Portable Windows Cleaner and registry optimization tool. It can help keep your computer system running smooth, fast and at peak potential. Use it to remove unused files and remove invalid registry entries that clutter up hard drive and slow your system down.

Quicksys RegDefrag – Portable Registry Cleaner

Quicksys RegDefrag is a Free Portable Registry Cleaner or Portable Registry Defrag tool. It can be used to optimize and clean a system registry by removing fragments and empty space. The tool is simple, intuitive and easy to use. This registry defrag tool is compatible with Windows Vista, XP, 2008, 2003 and 2000.