Error 8504,104

I have what is described as an 8504, 104 error on my wife's PC, although a lot of remedies I have read on the forum involve being on the internet, which will no longer open (I'm posting this from my PC). her email works fine so it is not a router problem.

 

when we try and connect to the internet we get the usual "this page can't be displayed" message one gets when the internet goes down for any reason. then after clicking "fix connection problems" I get a windows pop-up saying "The Norton product is not properly installed. the product installation is broken" and a later screen (I can't remember the exact sequence that got me here)headed Norton Autofix error 8504, 104 stating that LiveUpdate has failed. on the latter I can't click the "Open Support Web Site" button as I can't get on the internet !  even the Norton icon on the desktop, although still there, doesn't now do anything. scary or what !

 

I'm way out of my depth here and hope this type of problem rings a bell with someone who can help us get back up ?

 

(Norton Internet Security, renewed on 3 machines 31/1/14, no problem with other 2.)