3750 have some memory bugs - so potentially hardware gone malfunctioning.
But you can try below steps see if the Luck Permits :
1. Turn off the device - remove the power 10min leave alone.
2. Try again hardware reset and check the console output ? (Hope you have console working before i take this as working ?)
3. what is the status of Front LED status when you reset ?
4. Make sure you use console port - check again some time we make mistake.
