Check if license file name is actually ends with ".wow2go" not
".wow2go.html". Some e-mail clients known to append ".html" (or
".xml" ) to the end of license file name.
Assuming that license file DOES have ".wow2go" extension, open context
menu (right click on the file) and go to "Open With" sub-menu. Do you
see WoW2GO as one of choices? Select it.
Andrei
Leaping Bytes, LLC