Anytime you make a change to your computer it is definitely recommended to do a system backup, create a restore point, or backup the registry.  The latter being most important when going into the registry to make edits for performing hacks and tweaks.  Simply put, the Registry stores all settings, options, and information for the Operating System, Software Applications, and Hardware.  The Registry is the heart and soul of a Windows OS.  Here is a quick and easy way to manually back up your registry without having to rely on 3rd party software.  This works with XP, Vista, and Windows 7.

Open regedit.exe through the start menu search or run box.

With the Registry Editor open, click on File Export and choose a location to store the backup file.  Name it something easy to remember such as "My Registry Backup".

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To restore your registry just navigate back to the backup and double click the file and click OK.