Looks like can’t stop trying to make life hard for other browsers. Or something.

If you’re running the same combination I am, and am annoyed that Outlook 2003 asks you to “Locate link browser” when you click on URLs in emails, and – if you do choose a link browser, like Firefox – opens two windows with the same URL, here’s a fix:

Fire up regedt32 and delete the following key, and all children: HKEY_LOCAL_MACHINE\SOFTWARE\Classes\HTTP\shell\open\ddeexec.

At least that fixed it for me.