Hi, I thought I had better post this. I was reviewing my /etc/X11/XF86Config-4 file in preparation for editing. I noted it was 'not usual' as it was generated by the Knoppix software. So, I reinstalled all. When I was setting up the X server again I chose a lcd monitor (this has worked before) and to my astonishment all works fine. Everything else I did was identical. Thanks to all who replied to this thread. gs