Question ASUS Black Screen when Bios Opens

Jun 16, 2019
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I have been given a computer with an ASUS P7H55D-M EVD Motherboard and ATI Radeon graphics card and can't get it to boot without the screen turning black.
I tried taking out the card and connecting via VGA, DVI & HDMI but no signal gets sent out. Apparently this can happen if the wrong CPU installed.
So I put the graphics card back in and after a lot of trial and error have now got it so I can get into the Bios but only for about 30 secs then it goes black. Before going into the Bios it lists some options and the last thing says the CPU Fan has an error however it appears to be working fine.
I managed to set it to default settings but it has made no difference. If I am super quick I can change one setting and save before it goes black.
What settings do I need to change? Or should I try reinstalling the Bios? Any help would be much appreciated. I'm not getting any error beeps and I can't get into Windows so can't make changes there.
Really would appreciate your wisdom / assistance.