Thanks for all the suggestions. Have tried them all, but NAV doesn't offer to create new rules. It simply doesn't check the email. Problem then progressed to not allowing any web pages to open, but that seems ok now.
Have looked at Symantec site, but no joy there. Followed their suggestions also, but no happiness!
Latest solution which seems to work, although only trying at moment. Disable Norton Firewall permanently, and enable Windows so that I at least have a firewall. It is definitely the firewall and not the privacy settings etc.
I don't think I can re-install Norton as it was an online purchase so I don't have a disk. It downloaded and installed and worked fine for 10 months, until last week
Will see how this option goes and will report back .... soon hopefully...
Cheers
HJ