Your Asus mb number says it's a proprietary board. Get updates from the company that made the computer it was used in. eg: HP, Compaq, Toshiba, Sony, Dell, etc. Or provide the computer information (brand and model) and I'll be glad to see if I can find drivers.
It may be the motherboard used in the Asus barebones Terminator P4 533A.
Downloading the manual shows a P4SC-EA motherboard.
You can check it against the manual here:
Note on page 10 where it lists the motherboard as P4SC-EA.
If that's what you have then the bios is here: