Having read some other posts I think I have answered my question. If I was somehow able to terminate my old (unwanted) account and Apple ID I would no longer be able to access the material I bought with that ID- so I'm stuck. I have to learn how to manage that situation.
This is unfortunate for Apple consumers. Life is complicated for families these days and this "rule" although it is in place to prevent cheating and fraud makes things unnnecessarily difficult for me and my family as in my niaevity (sic) with the online world I bumbled into this situation. Not everyone is out to rip off Apple - one of the worlds richest corporations- or the entertainers who market their work through iTunes.I would just like to be able to enjoy the entertainment I pay for where and when I like to on whichever computer is available to me. And I'm not terribly computer literate.
It would have been nice to have had the opportunity to speak just once to a real person in the employ of Apple to explain my situation to them.
You can't currently delete an account, all you can do is remove any personal info from it and stop using it. But any content that you bought/downloaded with that old account will remain tied to that account, so you will need to continue to remember its id and password in case you want to authorise it on a new computer or re-download its content.