You mentioned that you clicked on the canreef link, are you doing this from a search engine or from a bookmark in Chrome or from someone's website?

Charles

It's from a bookmark in a "message boards" file in "other bookmarks".
No pop up this time.

Do you get a popup if you type in the URL www.canreef.com instead?

I've not tried that at all. When I got the e-mail about your post, I planned on typing in the URL, but unfortunately, when I'm viewing the salt water forums that I visit, I automatically do it in an order and method that I've done for many years and I automatically clicked on the bookmark instead of typing in the URL.
The pop up did NOT happen this time, and based on past experience, I can go just one more time, or sometimes up to 5 or 6 days before it happens again, and then it can happen 6 or 7 times out of the next 10. Nothing consistent.

Well, I did type in the URL this time and immediately checked the taskbar and found again, the ad page had appeared.
I had contacted Norton again and they told me to run Norton Power Eraser, but when I did, it came up saying nothing found.

Have you considered trying a different browser?

Not really. I won't use the Microsoft ones as I don't like to use anything of theirs if I have an alternate I can use. I used to use Firefox years ago but once I tried Chrome, I liked it so have used it ever since.
I won't change browsers just to avoid something that ONLY happens when I click on one site and no other site.
I'll keep plugging away until I find out how to stop it.
It would be easier if I was a lot younger and had the computer skills many of you have, but alas, with mild cognitive impairment, the skills certainly won't happen, and for getting younger, well.............
My Norton is up in a couple of weeks and I am going to Bit Defender so I'll see if they can pick up the problem. Norton told me to take the computer to a local technician to locate the problem and repair it. Why do I need Norton if I have to do that.

I tried Chrome for a bit on one of my older PCs that I could not upgrade beyond Windows XP due to hardware limitations. At one point I encountered a similar problem as yours, but much more annoying & affecting pretty well any URL I brought up. I believe I used the procedure(s) outlined by Gregzz in his post to mitigate it. In the end I ditched Chrome as none of the other browsers, including Windows Explorer were affected. Definitely seemed to be something in the way Chrome deals with cookies and I was unable to tweak any settings to solve the problem permanently. None of the 'big' Anti Virus software applications I tried were able to find & repair the problem. All they did/do is slow down my system unacceptably.

With Windows 10 on my current notebook, I'm sticking with Microsoft's Edge browser & have removed all 3rd party anti-virus software, opting to also use the Microsoft protection system which is free and I haven't experienced any virus issues.

If you don't wish to or are unable to try any of the solutions or suggestions provided here, then really your best option is to have someone with the knowledge & skills work on your PC.

Have you tried adding (add blocker plus) in chrome extentions? May be a easy fix

Mike, I've been using Chrome now for I think about 7 or 8 years on three different computers and never had a problem with it until now. I had switched up from Firefox at the time.
I tried to get used to Edge but change is not easy now at my age plus I have negative opinions on Microsoft anyway.
I just went on Edge earlier today but all I can find is settings to remove cookies at the end of session I think it was, not to block them period from ever being set, like I can with Chrome.
I did try the things Charles mentioned but no change.
I'm not skilled enough to try what Gregg mentioned.
Cost to LOOK at the computer starts at $80 and when on limited income it's the last thing you want to do.

Ryan, I don't know what chrome extensions are, or anything about this add blocker plus you mentioned. Most things are not easy for me on a computer unfortunately.

Another weird thing is that my tablet doesn't have this problem and it has exactly the same things on it with the same version of windows 10. I only use it for message boards when I'm away from home though as it's too hard for me to type on.