iPod screen flashing on and off after most recent download

I downloaded the most recent iso update to my iPad Original and when it came up after the download, my screen started flashing on and off and would not stop flashing. I restarted it and then hooked it up to my laptop and tried to sync to itunes, but since I couldn't type in my password (the screen was flashing too much), it wouldn't log into itunes. So I restored it and it is still flashing, this time with a "click" sound, like a camera. Help! What else can I try? I have completely restored it to factory settings but it is still flashing on and off. It was not doing that before I downloaded the most recent update and it started doing it immediately after the download. Is there a way to undo the recent update?