These popup ads are the bane of my life.
I've contacted Magix for both web designer and graphic applications. In each case I received a reply showing a gear icon at the bottom of the ad...I did not see it.
Hiding the taskbar, right clicking and choosing move, I raised the ad window and there it was...but I could not click it as it returned beneath the screen edge as soon as I released the mouse button. Arrow keys did nothing either.
My solution was to go to display settings and change the screen orientation from Landscape to Portrait. I then had the gear icon in sight and clicked do not show ads.
Once done I returned to Landscape.