registry

Yes, there are many ways to backup the registry. It depends on what OS your using and which way you want to do it? Here are a few examples.....

If you have Windows NT/2000 you can use the included backup program located in: programs\accessories\system tools\backup in W2K and programs\administrative tools\backup in NT.

If you have a Zip or Jaz drive you can use the free software that comes with it to backup your registry.

You can also use regedit to backup your registry. Note: I cut and pasted this from the Regedit help file.

To export all or part of the registry to a text file

On the Registry menu, click Export Registry File.
In File name, enter a name for the registry file.
Under Export range, do one of the following:
To back up the entire registry, click All.
To back up only a particular branch of the registry tree, click Selected branch and enter the name of the branch you want to export.
Click Save.
Note:
You can use any text editor to work with the registry files you create by exporting. Registry files are saved with .reg extensions

Actually, if you wanted to the extention to not be associated with an application, you could do that, but the easiest way I have found to back up your registry is to go to the DOS prompt, change the attributes, copy the system.dat file, then change the attributes back. The following DOS commands will do exactly that. (Note that I will name the backup registgry system.bak for this example)

cd windows (unless you are at windows)
attrib -s -h -r system.dat
attrib -s -h -r user.dat
xcopy system.dat system.bak
xcopy user.dat user.bak
attrib +s +h +r system.dat
attrib +s +h +r user.dat

This way you have a good clean copy of a specific date and can keep as many backups that you want.