I've been using it without any problems until one day I decided to use the sleep function (pressing the sleep button). When trying to wake it up - the screen never lit up. Pitch black. Dead. I'm looking for some advise that can help me identify the faulty part; The GPU board (NVIDIA Quadro 2000M), the Decoder board or the LCD itself? If I connect an external monitor to the PC, it boots up just fine and can be used, but the Device Manager only shows the Basic Microsoft VGA Graphic card Driver. This suggests perhaps that the GPU board is defect since it appears not to be detected at all (?). But is there a way to find out for sure? If it was the LCD panel itself, I would at least expect the backlight to come on. The result of a defect Decoder Board is very unclear to me. Would the BIOS be able to "see" if the Decoder Board is defect, and thus ignore the whole GPU during POST? Also, I was wondering if it is possible to ditch the Dreamcolor LCD and put in a regular LCD instead? Is the output port on the GPU a "normal" eDP port, and can I thus use a regular 30 (or 40) pin cable to drive a regular non-Dreamcolor LCD panel? Any advise is appreciated. This PC, although old, is still a high end device with 1Tb SSD and 32Gb RAM.