If your bios firmware has become corrupted and you have a similar motherboard with the same CPU socket and a bios chip of the same type, you may be able to recover your corrupt bios if you are willing to risk the other bios chip.
Take the non-working bios chip out of its motherboard and set it aside to keep it safe.
Take the working bios chip out of the working motherboard and insert it into the other motherboard, but do not press it all the way into its socket. Only place the chip so that its connectors are touching the sockets contacts firmly.
Attempt to boot the motherboard with its temporarily installed bios chip.
You must get the system booted to a floppy disk which contains the correct bios and installer for the broken motherboard. Do not flash the working bios chip.
Gently use a chip puller or pair of small screwdrivers to remove the working bios chip from its socket.
Be careful not to touch anything metal with the tools, as you must leave the system running for this. Set the working bios chip aside.
Insert the corrupted bios chip firmly into the slot in the running motherboard.
Again, be careful not to touch anything metal.
Flash the corrupted bios following the instructions in How to Update Your Computer’s BIOS.
Cross your fingers and reboot.
If it worked, reinstall the working bios chip back in its motherboard.