1. Reinstall the program in question if the error message mentions one. Registry fail error messages vary greatly and are often difficult to analyze. However, if the error messages specifies a particular program, tru to uninstall it and then reinstall it. Occasionally, applications might not be properly configured due to system bugs or user interruption.
2. Reinstall the required device driver if the error in question regards a hardware failure. A common type is undetectable. Take note of the specific error message and reinstall the appropriate hardware device.

3. Write down the exact registry error code in the event it is too difficult to understand. Research the code online. Users who have had similar issues might offer a solution to the registry error in question.
4. Undo your last action if you cannot pinpoint the cause of the registry error message. If no major clues come to surface, remove the last application or device driver installed. Revert to your last known setting in the event you heavily modified any system preferences.
5. Perform a Windows System Restore to undo all system modifications at any given date. Use this procedure if any recent actions or activities performed have been forgotten.Go to 'Start' followed by 'Programs.' Click 'Accessories' and 'System Tools,' then launch the 'System Restore' utility. Click 'Recommended Restore' to undo the most recent changes made to your computer. Otherwise, click 'Choose Another Restore Point,' followed by 'Next.' Select the available list of restore options, which are listed by date. Click 'Next' followed by 'Finish' to initialize the procedure. Save all your current work before proceeding.
6. Use a third-party registry cleaning utility if all else fails. Registry cleaners help eliminate program entries which are not connected to any software, hardware or system settings. They clean up the registry of any potential invalid keys or commands. In turn, any registry fail error messages might be effectively resolved in the process. Popular applications include Registry Mechanic, Comodo Registry Cleaner and EasyCleaner.