Backup and Restore for Windows Registry
The Windows registry contains five main keys and countless sub-keys under the main keys. You can backup the entire registry, a set of keys, or a particular key - whatever you want. The most widely options used to backup the registry are Reg file and Hives.
Registry Backup to Reg Files
This option creates an editable registry backup file. You can edit the backup file using Notepad or any other text editor. The most common method of exporting keys of the XP Windows registry, the backup can be merged into current, active registry using a double click or a right click.
DOWNSIDE 1: If you double-click, the reg file is added to the registry after a confirmation dialog. If you accidentally click YES, you add an incorrect backup to current registry.
Restoring .REG File: Right-click on the Reg file and select Merge or use File -> Import in the Windows Registry Editor. When you use this method, the backup is checked for relevant keys. As the keys are found, they are replaced by the backup.
DOWNSIDE 2.2: If some key (in backup) is missing in the current XP Windows registry, it is also added to the current Windows registry. This usually happens when you uninstall any program and later restore an old backup Reg file.
DOWNSIDE 2.2: If you changed a value of any key using the Windows registry editor, the key will be overwritten with older data (in case you made any changes to the backup using Notepad).
Overall, this method is good if you are sure that you will not delete or alter any keys in the backup .reg file.
Registry Back up to Hive Files
Selecting this option will create an image of the selected key in binary format (not text).
Downside 1: You cannot edit the hive file (backup file).
Downside 2: You cannot export the entire registry into a single file using this option. If you try to backup the entire XP Windows registry by selecting My Computer icon, you get a message that the key selected is invalid.
Restoring Registry Hive: You can always add it back to the Windows registry using File -> Import option.
Overall, this is the XP registry keys best backup method if you do not intend to make any changes to the exported file. Of course, the other downside - missing keys- apply to the Hive method too.
Other Backup Types for Windows Registry
Text File: Exporting the registry or XP Windows registry key using this option creates a text file. You can view and edit keys on Notepad but cannot merge this back-up into XP Windows registry.
Win9x/NT4 .reg Option: This option creates a Reg file similar to the first type. The only difference is that the backup created using this option is compatible with older versions of Windows. It would be a very rare case when you would export one computer's registry to another!
Now that you know the pros and cons of different types of registry backup, you should be able to select the option that best suits your purpose.