Re: Anyone know how
Norton isn't as good as you think it is I'm afraid. But then there is no anti-virus package that can protect you from everything, so you have to use a combination of products that work well together.
OffersByContext is Adware/malware so not a virus as such.
To remove it you will need to download and install the defacto/industry accepted benchmark product called Malwarebytes. You can download it free if you just want to do a one-off manual scan to detect and remove malware on your PC. If you want it constantly running and detecting malware as it arrives then you have to pay for the package same as any other PC protection program.
It is very easy to download and run malwarebytes and you'll probably be amazed at how much malware is on your PC. A warning though. Before running it you need to adjust its settings. It detects what it calls "Potentially Unwanted Programs" (PUPS). A lot of the time that is genuine stuff you may have deliberately downloaded to your PC or which came installed with it. What you don't want is the Malware scanner to detect it and remove it, which is what it will do by default. So in the settings you simply tell it to "Not Clean" or "Not remove" PUPS (can't remember the exact wording).
If in doubt get your best friendly PC geek to do it for you.
Good luck