Few Registry Freeware to keep your system registry optimized and clean :
Eusing Free Registry Cleaner : Eusing Free Registry Cleaner is a free registry repair software that allows you
to safely clean and repair registry problems with a few simple mouse clicks.
PageDefrag : Popular SysInternals utility performs Registry and Page File defragmentation.
Wise Registry Cleaner : scans the Windows registry for invalid or obsolete
information and presents you with a list of potential problems. To help you
decide which items to delete, the program classifies them as `Safe to fix` or
`Not fully safe to fix`. A built-in registry backup enables you to undo any
changes, should problems arise from a clean-up.
RegSeeker : is a handy tool for managing several popular registry items and
searching the registry by keyword. It offers quick access to Startup Entries,
Uninstall Information, Color Schemes, History items (URLs, Recent Documents etc)
and IE Favorites.
CCleaner : Apart from cleaning system it also have advanced features to remove unused and old entries, including File Extensions, ActiveX Controls, ClassIDs, ProgIDs, Uninstallers, Shared DLLs, Fonts, Help Files, Application Paths, Icons, Invalid Shortcuts and more... also comes with a comprehensive backup feature.