Update killed my tablet

Updated a brand new a7-20f and it looked like it completed successfully, however, now all it does is vibrate and flash the backlight screen every minute or so. There does not appear to be a hard reset button on this device (there's a tiny hole for one but nothing to be pressed). Holding the buttons in any given combination for any given amount of time does nothing. Computer fails to install drivers and the connect/disconnect noise goes off randomly. Did I mention that this is the second device to do this? As in this is the replacement for the first one that did the same.