How to Restore Previous Versions of the Registry in Windows 7
If you want to manually restore a specific section of the registry from a previous System Restore snapshot, or access some specific keys from an older version of the registry, you can do so by getting access to those files and then exporting sections from them. Here’s how to do it in Windows 7 or Vista.
Since Windows 7 and Vista utilize Shadow Copy, otherwise known as Volume Snapshot Service, to power the “Previous Versions” feature, there are snapshots of important files taken over time, including registry hives, so we can access the older versions of registry files this way without having to do a full System Restore.