Why do ads pop up out of nowhere?

[Android Central Question]

Sometimes im just at my homescreen or in a game and ads just pop out of nowhere, this has been present for a while but i thought it will go away but its starting to iritate me and i cant get rid of them, 2 things usually hapen, or an ad just pops up and covers the hole screen (and doesnt even count as an app so i cant press home and get rid of it or swipe to close) and there is a small X or chrome just opens by itself on to a page that i didnt open, the second thing usually hapens when i access my tablet after inputing my password, everybody says its just apps(from what i read) but most of the apps i have where installed after this started. PLEASE HELP!!!!

 

[B. Diddy]

Welcome to Android Central! You most likely installed an app that came with adware. Uninstall apps one by one until the problem goes away.