Challenge? No video signal – ATX form

Brought a PC home from friends house to add RAM. Using my monitor after replacing RAM, I now can not get a video signal.

Thought it might be flaky power supply, I replaced power supply.

Tried a previously working card, new card – all fourPCI slots. No signal – Monitor is good on another PC.

I have unplugged all boards, connections except for floppy and CPU fan and video card.
Reseated many times.

Could it be my VGA monitor (Impression 7) may not be compatible with friends video card?

Any ideas?