MY phone (Samsung S3) just went off today and started flashing the Samsung logo. I have taken out the battery multiple times and tried to restart the phone. Only once did it restart but then after ten minutes went back to the logo. I tried to press HOME VOLUME UP and PWOER and nothing happened. Then i tried HOME VOLUME DOWN and POWER and i got the screen for Support Help! Warning!! A custom OS can cause critical problems....after a while it goes back to the logo flashing. I cant restart or reboot my phone.