1. Take battery out.
2. Put it back in.
3. Power on phone.
4. When it's at the Samsung animation boot logo hold the volume down and up button and repeatedly hit the touch sensitive buttons.
5. Keep doing this until you get a 'Safe Mode' text at the bottom mode
6. Then release all keys and navigate to phone settings, applications and look for the 'System Update' app which should be located under downloaded applications. Uninstall this application and restart your phone.
7. Your phone should boot up and be out of safe mode and the virus should be gone.
Usually this application is disguised as 'System Update' but could be disguised as another application.