Error Nuker is a product by Trek Blue Software,that is supposed to find and fix errors in the Windows Registry before they become problems and cause your computer to not boot into Windows or startup at all.

 Feature Highlights:
Automatic Scan
  By default, Error Nuker scans the registry for all types of errors. This is the simplest way to clean up the registry. Automatic Scan is recommended for 'non-technical' users.
Custom Scans
  You customize your search and scan Windows registry for particular types of errors (shared DLLs, missing fonts, invalid startup entries, etc.).
Manual Cleanup
  After the scan is complete, Error Nuker will show you a full list of errors with details, broken down by types and let you fix individual invalid entries or all invalid entries of a certain type.
Backup and Undo
  Before removing an entry from your registry, Error Nuker automatically creates a backup file that can be used to undo the changes.
Scheduler
  You can schedule Error Nuker to scan the registry whenever you start your computer.
FREE
  Error Nuker will scan Windows registry and give you a detailed list of errors broken down by type Absolutely FREE.