In an earlier article I discussed using system restore to backup and restore registry in windows vista. However there is a simpler way to do this.
Simply start regedit (Open Start menu, type regedit in Start Search and click OK). Now go to File>Export.
Select All under the export range.
Enter the name of the registry file and choose appropriate location to save the registry file. This file will hold all the information of the registry.
To restore the registry to a previous backup (that you created using the procedure described above), start regedit (Open Start menu, type regedit in Start Search and click OK). Now go to File>Import, and choose the backup reg file. That’s it. All the settings from the backup file will be restored in the registry.