When I connect my s3 to charger, the screen starts to act very strange: it is impossible to enter the pattern or PIN, and screen remains blocked when receiving calls. This problem started a week ago, before that I used my phone for a year without any problems. Android 4.1.2, not rooted. It started when I connected to internet, so I thought it could be a virus or a hacker, but avg, avast and lookout did not find anything bad.