Sounds like something got installed it might be a 'helpful' but intrusive adware thing supposed to show ads related to what you are looking at.
It might be sort of legit and a simple uninstall from programs and features, look in there and sort by date see if anything unexpected is listed.

If nothing shows there, it's not really an adblocking job more like malware by the sound of it.
Malwarebytes would be first thing to try, the free version might be enough.