Wise Registry Cleaner (portable)

Wise Registry Cleaner Portable is a registry cleaner and optimizer packaged as a portable app, so you can work on PCs on the go. It's freeware for personal and education use. Like many system utilities, this requires admin privileges to run.

Wise Registry Cleaner includes a fast scanner to check for registry problems. It can backup the registry to ensure it is safe to restore. It has the ability to defragment the registry (note that it will require a reboot so ensure all your apps are closed and it will give a warning about not shutting down properly when run again). The interface is very easy to use for novice users and pros alike.

http://portableapps.com/apps/utilities/wise-registry-cleaner-portable