You can make full or partial backups of the Registry from inside the Registry Editor itself (REGEDIT.EXE). The backup is stored as a .REG file in the location of your choice, a folder on your hard drive, on a network drive, or even on a floppy disk - if the file is small enough to fit (but chances are, if you're doing a FULL backup, it won't be).

To back up the entire Registry, open the Registry Editor, (Click Start/Run, type "regedit" (without the quotes), and click OK. Make sure and highlight "My Computer" in the left pane. Pull down the Registry menu and choose Export Registry File. Type in a File name for the backup you're about to create, then navigate your way to the folder where you'd like to store the backup (a full backup usually won't fit on a floppy disk, for example, our backup was 2.67M bytes). Finally, make sure All is selected under Export range, click Save, and wait as the .REG file is created.

If you're working on only a small area within the Registry, you can back up just that part. With the Registry Editor open, navigate your way to the branch you'd like to back up. (A branch is a key, or entry, in the Registry, and all of its contents.) For example, you may want to just backup the HKEY_USERS branch. With the key at the top of the branch highlighted, choose Export Registry File from the Registry menu. In the resulting dialog box, you'll see the highlighted branch listed under Selected branch. Now just follow the same steps as before to create a full backup, name the REG file, navigate your way to the location where you'd like it stored, and click Save.