NAV Won't Start

Greetings,

 

I turned on my computer today, and I got a message in the Action Center asking me if I want to turn on NAV. I've had this problem before.

 

It appears that there were four updates installed during boot-up, and one of them has caused the problem (but I'm not sure which one).

 

Norton Smart Virus Definitions X64
Norton Pulse Updates
Norton 2013 Whitelist
Norton 2013 Reputation Revocation List

 

Is it possible to diagnose which of these updates is causing the problem?

 

Thanks,

Shane.