AC adapter not recognized message = the adapter recognition circuit in your adapter has failed. The adapter will still be putting out the correct power wattage, but the computer won't recognize it as a Dell adapter and will penalize you by closing the battery recharge circuit and slowing the processor speed. Other than that the computer will continue to work fine. The solution is to buy a new adapter. From experience my 3 adapters lasted <12 months before the recognition circuit failed. Think of them as a consumable item rather than hardware.