If it were me, I think I would purchase another HDMI cable and try that. It's possible your cable is faulty, and has an electrical short. Of course, it could be the connector on the laptop, even the monitor.
Also, is your BIOS and graphics / video drivers up to date?
Thank you for answer. I Just tried now a hdmi cable from my xbox one, and another one with no success. I also change termal paste. Temperatures are ok even on heavy load.
OK, first, if you plug the HDMI cable into the laptop, but you do not plug the other end into the monitor, does the unit reboot?
Second, do you have a means to test your laptop with another monitor? (Computer store, friend's house, work?)
OK you have done some good debugging. I would uninstall the driver and re-install the most recent driver. Your BIOS should be up to date as well.
Wow. So - at this point, I suppose I would try the display port connector on the side of the laptop. What type of inputs does your monitor support? If HDMI only, I would try a dP to HDMI adapter or cable.
Let me ask a few more questions: what type of power adapter are you using? Is it an OEM power adapter? Is it 180W? If it is not providing the proper output, or if it is somehow providing a grounded output at a different potential than the monitor, then connecting the two devices together may result in a reboot.
If you've only been testing the M4800 with it plugged into it's adapter, try disconnecting the power adapter and running on battery... then connect the laptop to the monitor. Does it reboot?