How to backup your registry
Before you try to edit your PC's registry, make sure that your first export the keys in the registry that you plan to edit, or back up the whole registry. It is a very good practice to always backup your registry because if a problem occurs, you can just restore your registry to its previous state.
These are the easy steps on how you can export your registry keys
► Click Start, and then click Run.
► In the Open box, type regedit, and then click OK.
► On the File menu, click Export.
► In the Save in box, select the box at the bottom the bottom according to weather you want to export all or only selected branches of the registry.
► Next select a location in which to save the backup .reg file. In the File name box, type a file name, and then click Save.
Follow these steps to restore your registry to it's previous state
► To restore registry keys that you exported, double-click the .reg file that you saved.