Couple of times in the past few weeks I've had adware pop up on screen when opening up my PIA screen. It's happened often enough that I know it's this site that is triggering it somehow. You get a full page ad open up on screen and by clicking on the X to close it, that enables adware which then puts ad-links on any future page you try and open. You get random words underlined in green with a clickable arrow next to them.
For anyone else getting the same thing, you need to go into tools on your browser - on Chrome for instance I click on the three lines at the top right then select More Tools, then you choose Extensions, and you'll probably find right at the top is some spammy ad site with the 'enabled' box selected. Deselect and bin - and run some software like MalwareBytes (i think that's what it's called) regularly.
I'm no sort of computer expert (obviously) but if it's happening to anyone else, I thought this might be useful