Phew what a relief someone else has the same problem! My LiveUpdate has suddenly stopped too. It has worked perfectly well for the last 3 years. Message says "Unable to connect to ISP please check your internet connections" Obviously they are ok as I am doing this. Have checked with my ISP also no service problems. Have checked Symantext site and emailed them for help also.
Any ideas anyone. I believe there is something somewhere on the computer who can see what has automatic internet connections etc can you tell me where to find it as LiveUpdate should be listed in there.