Hi and welcome to Just Answer. My name is XXXXX XXXXX will be assisting you today.
If you have a corrupted Bios, nothing would show up on the screen. The only way to correct this problem is to either replace the Bios Chip on the Motherboard or use a floppy disk to blindly reflash it. You would need to get the Binary File from HP and copy it to a floppy. You'll need a Floppy Drive attached using a Ribbon Cable.
If you can't get a replacement Bios Chip or Binary Flasher, replacing the Motherboard will be your last option. Hope this helps.
Thanks! Will give it a go!
You're very welcome Freddi and good luck!