What if I had a corrupted backup or no backup. Is it possible to still make a working bios? Anyone

What if I had a corrupted backup or no backup. Is it possible to still make a working bios?...

5 long beeps and 2 short beeps still. Any clue. I have also done this bios almost 20 times by different ways. Any one to help...

Hi ! I am new to this forum. I am struck at the bios of hp prodesk 400 g2 mini. I have a repair shop and and normally do these repairs without any problem mostly hp 400 g2 etx but this one PC had a corrupted bios, fan spinning all OK but no display. I did bios by changing bios region through hp website by serial No. but its not working. Now it gives bios beeps 5+2 beeps. I have tried many times but in vain sometime fan spin at full speed and sometimes beeps ,. Now i am thinking that maybe i have problem in backup of bios. But i doubt as i have only one backup.
Kindly help me i am posting...

Hi! I am Qureshi. I am from Pakistan and Computer Engineer....