How can i stop full screen pop up ads on the acer tablet?

[AC Question]

Almost everytime I turn on my tablet, my browser instantly opens and directs me to a page that says something sketchy like: "congratulations! You are a millionare!" Or it opens the Google play store and shoves some irrelevant ad for an app in my face, and it's allways full screen. It's driving me MAD. Can this be stopped? If so please help!!