Interesting, simple, example on using the group policy editor. Specifically, using it to disable autoplay on CDROMS in WinXP.
Grabbed from Deja.com:
How to disable Auto-insert notification on CDROMs
microsoft.public.windowsxp.general
Date: 2002-02-13 14:10:55 PST
Start, Run, GPEDIT.MSC Computer Configuration, Administrative
templates, System, Turn off autoplay.
To Disable CD autoplay, completely, in Windows XP Pro
1) Click Start, Run and enter GPEDIT.MSC
2) Go to Computer Configuration, Administrative Templates, System.
3) Locate the entry for Turn autoplay off and modify it as you desire.
Note: It might be easier to just grab TweakUI and use that. Although it doesn't seem to work that well...
Note 2: This works in XP Professional only. XP Home does not come with gpedit.msc.