Installation - not even NPE seems to work

I am trying to install Norton 360 on my desktop.  I have downloaded the, erm, downloader (N360Downloader.exe), and launched it.  After a variable spell of "Initialising", a message comes up: "Automatic installation cannot continue.  Click Open Browser for instructions on how to complete the instalation manually"  Clicking Open Browser opens another window (looks like Google Chrome), searching for www.norton.com/fo/  Almost immediately, the page shows "400 Bad Request  Bad filename".

 

Checking the error console on Firefox, there a message: "account.norton.com : server does not support RFC 5746, see CVE-2009-3555"



I have wondered if the computer could be heavily infected, so dowloaded NPE (Norton Power Eraser).  This appears to run okay, if briefly, then tells me that  it has successfully restored internet connection; I didn't know I had lost the connection - and how did I download the prog?!

 

Any suggestions of where I am going wrong, and how can I correct it?