Your board manufacturer will have a set of bios files on their website. If you can get to another computer and d/l them, they will work. you will have to create a startup disk with the format utility, and then copy the awdflh.exe file and the bios file that come with the d/l to the floppy disk. Then when your computer boots up pop this disk into it, and have it boot from it. It will load up to a dos prompt.
Then enter the command awdflash.exe *enterbiosfilenamehere*.version number and press enter.
Ex. For one of my boards i would do A:/awdflash.exe v7030vms.360
Make sure there is a space between the command and file to use. This should fix your problem
Also I just went to the ASUS website to check for the files for you, and it says your board, assuming I have the correct one (A8N32-SLI Deluxe)
is an AMI BIOS. which means the above command would be wrong.
Instead the utility and bios files are located here:
http://support.asus.com/download/download.aspx?SLanguage=en-us&model=A8N32-SLI Deluxe
You are looking for the DOS one, not the ASUSupdate tool, because you can't get into windows.
And the version you would want is 1303. The newer ones are just betas. Let me know if this works.