Thanks Amy - it may well be the browser situation. When one accesses You Tube (and presumably has an 'out of date' browser bu You Tube standards), the message " your browser is no longer supported. Please upgrade to a modern browser" appears and Mozilla Firefox is the very first of the suggested five alternatives.

Also just luck too I imagine, since despite the announcement, I have been able to watch and hear a whole variety of clips on You Tube with no problem, but Susan's may be the exception.

Kerry