I'm thinking i may have a virus or something on my s4. I downloaded this live wallpaper app and it decided to download more apps and spam me with ads constantly. I deleted the app, but ever since then my phone seems to be acting laggy and on numerous occasions after pressing the home button it will go to a blank screen with only the app button in the middle. Is there a way to do a hard reset and backup my info? Or something that can scan to get my phone running normal again? Thanks.