I'd like to use a default Windows icon for the autorun.inf on a USB drive.
How can I extract an .ico file from SHELL32.dll?
You can do that with any icon editor, e.g. IcoFX:
It's free, and very easy to use. You choose a .dll or an .exe file, and open it in IcoFX.
This article helps a lot: http://www.techsupportalert.com/best-free-icon-editor-and-replacer.htm
It includes freeware software that includes the last freeware version of IcoFX. Otherwise, the main one that it touts is Greenfish Icon Editor Pro, which I'm using right now. One of the best parts about them is that they're not time trials.
Here's the official Greenfish Software Blog: http://greenfishsoftware.blogspot.ca/2012/07/greenfish-icon-editor-pro.html . It features the latest version (3.31) as the latest post.
IcoFX does not otherwise provide an official link to their last freeware version.
And if these don't work, there seem to be more suggestions in the comments section of the article.