Regedit edits the Windows Registry. (There was another registry editor known as regedt32, which had a different look. If you launch it, it just brings up the standard registry editor.)
Changes made in Regedit are automatically saved when you exit; however, you might have to log off and lock back on, or restart the system, for those changes to take effect. Under most normal circumstances, the Registry will not need to be edited or viewed. However, Registry editing might be necessary under the following circumstances:
• To view a system setting that cannot be viewed through normal interfaces.
• To add, modify (by changing values or data), or remove a Registry key that cannot be changed through normal Windows menus or application settings. This might be necessary to remove traces of a program or hardware device that was not uninstalled properly, or to allow a new device or program to be installed.
• To back up the Registry to a file.
Caution: The Registry should never be edited unless a backup Registry copy has been made first, because there is no Undo option for individual edits and no way to discard all changes when exiting Regedit.
Editing the Windows Registry is even more difficult because registry keys can be expressed in decimal, hexadecimal, or text. When editing the Registry, be sure to carefully follow the instructions provided by a vendor.
Follow these steps to back up part or all of the Registry to a text file:
Launch Regedit (open the Run prompt and type regedit, and then click OK), and do File | Export.
Pick a folder for the Registry backup. (To back up the entire Registry, highlight My Computer/Computer at the top of the left window pane, or Select All to back up the entire Registry.)
Name the file, and click Save.