Some Shields are turned off

I have three AVG subscriptions (AVG Ultimate Militi-device, AVG Tuneup Multi-device and AGV VPN multi-device). Today when I booted my computer that is two years old, AVG Internet Security had a warning that "Some shields are turned off". Out of four shields only the computer was protected. I clicked the button to "Turn On" and they all changed color from red to green and it said they were protected. In less than 10 seconds the same three shields turned red - Not Protected again. I rebooted several times before calling AVG. Tech support did a remote session and said that some old Norton software was causing the problem. I told him I never put Norton on this computer. He said it is something that come with the computer and that was what is causing the problem. He then tried to sell me $199.00 service to fix it. It seemed like a scam so I ended the call. Is this real??? Why is something that has been in my computer for two years now causing this problem???