DIAGNOSIS Corrupted monitor firmware. This is a common issue after a failed update or from a factory bug.
FIX Force a firmware reflash. Download the latest firmware for your exact model (S32AG75 or S32BG75) from Samsung's support site. Unzip the file onto a blank FAT32-formatted USB drive. Power the monitor off at the wall. Plug the USB into the monitor's service port. Hold the joystick button on the back IN (towards the screen) and power the monitor on. Keep holding until the update screen appears. Release. Let it complete.
IF THAT DIDN'T WORK The main board may be faulty. A power cycle can sometimes clear a transient fault. Unplug the monitor from power and from the PC. Hold the power button on the monitor for 30 seconds. Reconnect only power, turn it on. If the boot loop persists, contact Samsung for a board replacement.
HEADS UP Never interrupt power during a firmware update. It will brick the monitor.