Thanks to you all, sorry:
Dell Inspiron One, a sort of laptop expanded to a desk top screen, the 'works' are behind the screen, only one wire required. Using MS Windows 7.
I can get the Skype 'attention' call incoming, after changing speaker settings, but cannot hear the voice, still working well on my laptop using the previous version of Skype. As it doesn't appear to be a common fault I'll go back through all the settings and match them to my laptop. Not holding out a lot of hope though. Any more ideas much appreciated.