Ok, thanks for the tips. Nothing came up on Malware scanner and the Adblock didn't work. Luckily I found out what was causing it.

A program/extension called Digital More Ads had installed itself (I assume it was bundled with something I downloaded). I just had to go to Extensions Manager and disable it. Annoying software... looking into removing it

Ok, so I've been using Opera for around 15 years, and I've never ever had cause to come to a support forum for it until now.

In all of those years I have almost NEVER seen a pop-up, advert, background-loading ad, whatever. They just haven't existed.

Today I browse, and find a load of underlined words in all the forums I'm on, and each is an advert. Clicking any link can spontaneously open a pop-up or background tab. Googling anything is beleaguered with a million ad-sites pestering the top of the list. WHAT IS THIS???!

I figured it out. I was using Opera 28, and somehow managed to "upgrade" to 29. In 28 and previous I have never needed an ad-blocker or noticed any ads etc. Now it's horrific

How do I fix this? Please don't say "get an adblocker"... Thanks to Opera I've lived without having to get addons and blockers for over decade