My acer aspire laptop suddenly stopped working while it was connected to my nokia mobile modem through usb. It stopped with power swich staying on and no response to clicking off, no irregular sound, nothing but just a blank screen. I disconnected the power and battery quickly but power switch did not respond at all and even the power indicator didn't turn on again. the display was also gone after disconecting the power and removing battery. It has no response or any sign of power while both battery and power supply are working. What do you think? A completely dead mainboard? Does the MB has any safty board or fuse that could be replaced? Any suggestion will be appreciated, Thank you.