I got it ! yeah ! Here is the way that worked for me, hoping it will be of some use for someone one day : - Turn off computer - Disassemble chassis in order to unplug battery and KRT battery (not sure if necessary) - Push power button for 30s in order to unload any remaining electrostatic charge - Put the power back - Maintain F2 and press "start" for 30sec Didn't worked the first time but after 2 trials, miracle, it finally worked. Thank you everyone for your help. Have a good day (I sure will).
