Do a hard shut off of the computer by holding down the start button for 5 seconds. Then restart the computer.
Check power management options in Control Panel; adjust/change the settings there (Obviously, if you cannot get the monitor to display, use a different monitor)
The monitor is not in Safe Mode, the PC is. Exactly what is happening, when did it start? Anything happen before this? If a reboot does not fix this, you may need to at least do a Repair setup of Windows if not a full re-installaton.