While you are searching the web for computer problems or tricks you may get some solution that told you to Edit or modify the Registry, before to do that the registry must be backed up, because if you deed any mistake and forgot the steps that made then its difficult to recover the registry for which you will face some problems in your PC.
So why not backup the whole registry first, to do that just follow these steps.
How to Export or Back up Registry:-
Click Start, then click Run
in the Run dialog box type regedit then click ok
the registry editor will open
on the file menu click Export
in the export registry file save in box chose the the location and type a file name such as backup then click save.
you can select the button at the bottom,whether you want to export all or selected branches of the registry.
Its always better to back up whole registry so let it be All.
How to Restore the registry:-
To restore the registry keys just double click the .reg file that you have saved and click Yes to confirm or Open the registry editor, on the file menu click import then select the .reg file and click on Open.