I just tried this tip out as I thought how could this be so silly an issue to resolve. No one is going to miss such an obvious delete button. Then I had a look at my own account. Clicking on a number of contacts did not display a delete button! I had to try a number of entries before I found someone who did display the delete key.

I think the issue is that I have connected my Gmail email account and my Live email account. The Gmail contacts cannot be deleted from the Live account (there is no delete key displayed for for Gmail contacts). I believe that the lady you are trying to help is probably experiencing the same problem.
Regards,
Jonathan Kelly