I gave up on most forms of anti virus software like Norton years ago since all it seems to do is fill up a PC with a huge amout of files and really slow it down - in fact virtually all the programs I ran for years have nowadays become incredibly bloated as they try to compete with each other on offering more and more "protection".
These days I use a completely different system with my router providing a complete stealthed firewall as the first defence.
The only HDD on my PC now is a single SSD for the OS, everything else now runs in an external SSD and all the files I need to keep safe are now on are external HDDs as further protection against malware such as Crytolocker (now superceded by other forms of ransomware)
The only things I use nowadays are Malwarebytes Pro in my host PC along with CyberghostVPN, all my surfing etc is now carried out in various VMs with Avast free in the VMs but only using the option to protect files enabled.
It's been a very long time since any form of attack hit my PC and the triple protection I have means that even if it did it could only attack the VM not my real machine and that could simply be shredded to destroy it completely.
And Symantec a few months ago said that attempting to even detect some of the newest malware was proving to be almost impossible with new ways of protection now needed.
In fact virtually all the attacks now taking place on the net are designed to pick the low hanging fruit, such as the attacks on USA sites such as Target, Anthem, Linkedin and of course Adobe where the attackers can get literally millions of account details and make vast amounts of money selling card details etc online.
And, as Sony proved, the bigger the corporation the more vulnerable and the greater the chance that lax or lazy employees could unwittingly help the attackers (at Sony they found unencrypted folders with the name "Password" on them containing the passwords to many executive accounts !)
And in many cases they can attack you and steal your identity without even needing to get into your computer (Google "Mat Honan - How Apple and Amazon Security Flaws Led to My Epic Hacking") to find out about his really bad day!
Nowadays I use 2 PCs, one which this is being written on, and my i7 PC for all my photo editing, video rendering is carried on and which is air-gapped and rarely connects to the internet.
And these techniques have protected me now for several years, and hopefully for much longer.