I have a computer - Windows 8.1 - that keeps going black. I tried undocking it and it freezes with a yellow flashing bar at the top when it freezes, tried replacing video cables, monitor cables, docking station. I suspect it's a hardware issue because of the flashing yellow bar, but an intermittent one. The laptop is a Lenovo T Series laptop. Updates, diagnostics, etc have been run but all clears. Have not checked the event logs for any errors during the specified time of outage. Any ideas would be greatly appreciated.