After installing some updates for FireFox, the Sharepoint Central Administration started to launch with Firefox instead of IE. We all have seen similar behavior in other places where the browsers compete to be the default browser, so I checked the default browser setting for IE.

It appears that IE is the default browser. I even tried to set FireFox as default browser and then reset IE as default, but that didn't help either.

Thanks to this post, I found the fix. It appears the set as default browser action doesn't reset the shell class in this registry location:

HKEY_CLASSES_ROOT\http\shell\open\command

After set it to use IE, Sharepoint Central Administration launches in IE properly.