We are suffering with serious problem. Here we are using avr studio 5 or 4 with avr mkII programmer to programme microcontrollers (atmega8515, 8535, 16, 32, 88, 168, 162, 128). Sometimes if we programme fuse bit with wrong value i.e. we have selected clock source external RC, but actually we wanted to programme with clock source external crystal, but now when we connect hardware with avr studio it shows error, even it cannot read device id. What should we do?