How to Backup Windows XP Registry

Making incorrect changes in the registry can break your system. It’s highly advisable to backup the registry before editing any portion of it.

Click Start -> Run
In the Open box, type regedit -> click OK
On the File menu, click Export
Select a location where you want to save the Registration Entries (.reg)
In the File name box, type a file name, and then click Save

To import the registry, just simply open up the Registry Editor and then click on File -> Import -> Select .reg file then click Open