Recent Apps not working

Recently I had to rest set my RCA Viking Pro 10 tablet because random ads for apps kept popping up out of nowhere. After the factory reset the ads stopped and everything seems to be working fine except the recent apps feature. I can close out of apps just fine but can't pull up the recent apps when I need to move between apps without having to constantly go to my home screen and click the app icon. Has this happened to anyone else when they've had to do a factory reset. I searched all through the setting for the screen/display option and can't find anything.