for what it's worth, Oldred, I have AVG antivirus running all the time, and it sometimes blocks suspicious websites, and Malwarebytes, which I only run every couple of weeks to make sure I haven't picked up any malware, but which is switched off most of the time. Both of these are free. AVG only very rarely blocks anything, invariably because I've clicked on a link to a site I know nothing about (clicking on links is what the internet is all about, after all) but which it thinks is dodgy.
Niether of them blocks Wikipedia for me. Norton antivirus used to block the Adverts section of AB, though.