How to Backup Registry - Windows?
The registry contains extended information, settings and various other values for the the Microsoft Windows 95, Windows 98, Windows NT, Windows 2000, Windows ME and Windows XP operating system. Within the registry you can control a great majority of the operating system as well as fix a lot of issues with Windows. However we only recommend those whom are experienced with computers or whom feel confident to go into the registry.

Backing up Windows Registry:

To backup Windows Registry from the Windows desktop click Start / Shut Down / Restart the computer in MS-DOS mode.

At C:\WINDOWS> type the following:

attrib user.dat -r -a -s -h
attrib system.dat -r -a -s -h
md backup
copy user.dat backup
copy system.dat backup

The above will copy the registry files into a backup directory in your Windows directory. Once the above has been done you can restart the computer and edit the registry as needed.