You can check if the VGA adapter is faulty and cannot be used.
You can try to link the U500 to the monitor first, and then turn on the power to see if it can be displayed.
Can you provide me with a purchase link for your VGA adapter?
I have seen that your driver is missing a lot. You can download this driver file, which contains all the basic driver files that you can install. http://www.mediafire.com/file/4txaac3ib9t9xr3/WB_Z83_drivers.rar/file
This is the original system file of GN31: http://www.mediafire.com/file/2qbsaf7aqc6mm9h/BLT-JX-MINIPC-M6JR120-BB80B-112-A1903.rar/file
Steps to reinstall the system: