Hi @dan82439
The problem will either be a hardware component or a corrupted Windows instalation - including drivers.
Did you get into Windows at any point with the external screen? You only mention "loggin screen". Did you try safe mode at any point? At loggin hold down <Shift> key and select Power and Restart (Note: angle brackets just to denote a keyboard key)?
Are the two fans working?
If you disconnect/take out the PCIe hard drive what does the internal or external screen display anything? Can you get into the BIOS/UEFI if either display works?
Swopping out one RAM module at a time may also be tried.