I accidentally installed an app that turned out to be a virus on my tablet. It was running android 4.2 at the time. After realizing about the virus problem (which was slowing it down a lot) i decided to do a factory reset thinking it would delete the virus. Now every time the welcome screen loads up, it quickly changes to a different background and when i try to do anything, it says "Unfortunately secret lock has stopped". I'm not very good with tablets and i have no idea what to do.