I ran a Full System Scan on NIS 2011 - it took 12.5 hours but it at least completed the scan. I shut the computer down afterwards.
When I later booted, NIS was gone. It took several clicks on the icon in start menu before I got One Click Support which listed the following error : Module 8504 Error 101
Started chatting with a Norton Analyst who wanted to connect to my computer to have a look, only no connection could be made. He sent me a link to NISDownloader for me to run ... after initializing for a while, the downloader just disappeared. He then suggested I try to download something not Norton related, presumably to rule out some threat based on Norton, so I tried to download updates for Mbam ans SAS only to be blocked out by the firewall ... although NIS had apparently gone, the firewall had blocked me out from downloading anything.
He then suggested I run NRT at which point I lost contact with him.
After running NRT I installed NIS 2010 which went ok then ran upgrade to 2011. The install got as far as 'restart for program to start protecting computer'. When I rebooted, NIS was gone again - I did get Norton Downloader constantly running without actually doing anything and that was it.
Ended up running NRT again and reinstalling NIS 2010 which appears to be fine.
Anyone else having similar problems ?