I need suggestions on how to proceed. I really just don't know where to start.
Can I force onboard video? I don't get any video signal, regardless of the output I use.
When you don't get any video output you would normally need to rely on any beeps emitted during the POST sequence. Does the computer make any beeps while booting? If so, how many?
You may also be able to force the on-board video adapter via a BIOS setting, which you will need to check the manual/documentation for.