A registry backup will only be of value...if you have a damaged Windows registryl. It is no panacea for any other situation.
The Windows registry is part of the Windows O/S...an important part, but only part of it. Your registry can be perfectly fine and Windows can have other problems that hinder proper functioning of Windows.
A corrupted install doesn't necessarily indicate a corrupted registry...since there are many Windows files which are not registry files.
To overcome a corrupted install which does not point the finger at a corrupted registry...the best tool is a full backup previously made which is without problems, IMO.
I also add the file corruption can be the result of a damaged hard drive...so I would check the drive before attempting any type of restorative action.
The Windows System Restore function does an automatic backup of registry, as part of the SR function.
Edited by hamluis, 14 January 2015 - 01:16 PM.