You can change the Drive Label (B in above post) much easier by simply right-clicking on the Drive (in My Computer, etc) and choosing "RENAME".
Once you've done that, it sets up the Registry structure that is explained above... so it's easy to add the new DefaultIcon key (as detailed in A) above).
OK, now that is the boring way... this little freeware program allows you to change the icons without editing the Registry.
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Get it from : http://www.brothersoft.com/drive-icon-changer-102805.html
You can use ICO files, or select a specific icon within a DLL file.
Note: I have only ensured that it works in XP, and not given it a thorough workout or checked other versions of Windoze..