How do I remove full screen ads?

[Sahil19]

I have a samsung galaxy avant that is 3/4 of a year old. Recently when I am connected to the internet (including 4G) full screen ads pop up on screen. Even on the home screen it pops up, but it pops up more while in games. I have avast antivirus and cm security, but it doesn't find the problem. The ads are usually about upgrading to windows 10 or getting an app from the play store.

 

[minion123]

Try factory reset. Back your data up. To do reset hold volume up, home and power button same time when turning ☎ on.

Posted via the Android Central App

 

[Sahil19]

Factory reseting will be my last resort. Is there any other way? Also is there a way to factory reset and keep all my apps and files?