Supporting Windows

Registry explanations:

http://support.microsoft.com/kb/256986

http://www.gammadyne.com/registry.htm

You are going to need to be more specific about changes. Through what method are you trying to make registry changes? Batch file, GPO, etc?

GPO:

http://technet.microsoft.com/en-us/library/bb727154.aspx

http://serverfault.com/questions/298047/push-new-registry-keys-via-group-policy

Batch:

http://www.robvanderwoude.com/regedit.php

http://ss64.com/nt/reg.html

Registries are registration information and customization information for OS and Softwares. This is the simplest definition I can give.

Windows Registry is where the configuration for the computer and users are stored.

You can use regedit.exe for a graphical browser of the currently loaded registries, where you can modify or add keys/values. 

You can export registry values as files with the .reg extension, which can then be imported as you want.

You can use the command line tool reg.exe to script out registry changes.