[rovert]

Thanks monkeybreath and iadom for your advice. When I checked LAN settings I found no address for secure server. After entering address and port suggested by MB I was able to access secure sites which were causing problems including goldfish which had been recommending upgrade to IE6! I have also used windows update finding 2 critical updates which I had not been aware of in spite of using automatic update option.
As far as Symantec is concerned I have now been able to run a check with their Automated Support Assistant which says I have an old version of Live Update. Although the necessary file seemed to download without problem the live update installer would not run to complete the installation. Looks like a full reinstall might be needed although zonealarm looks temting at present!
Still no joy with Mozilla Firefox (connection refused) but at least Internet Explorer working better.
Thanks again.