Sounds like you still have control power and DC power for the encoder counts...I would check the fuses for the high voltage supplied to the drives. Also, with e-stop in there should be no power to the servos- allowing you to move an axis by hand. Any binding? Binding will also cause this problem. Do you have encoder counts when manually pushing either axis? If so, the problem is likely in either the motor/tach(not likely that both motors are bad), motor cable(same senario), or a drive. Do the drives display an error?