For the last two days my Comcast home page has been re-directing to pages with message such as "Your Flash player is out of date" or "Your Norton subscription is expired" and others. Norton catches these as potential attacks and blocks them, but I cannot make the popups stop. Norton had me run their "power eraser" on my machine and clear the browsing history. Neither one helped. I have not seen this while browsing, only when accessing the Comcast home page. Using the MS Edge browser.
Sounds like you have malware. You can run a malwarebytes scan for free. Also google how to check your hosts file as that is one way they will redirect you, but there are also browser extensions and addins that can do this, there is info on google about that too. Try malwarebytes first.