Once you corrupt your BIOS you are screwed. Does you MB have a SPI header near the BIOS chip? You can use SPIPGM2.exe to load new BIOS but it is not easy.http://mondotech.blogspot.com/2009/05/asus-p5b-deluxe-bios-recovery-spi-flash.html?
I made a youtube video of how to fix with download links: http://youtu.be/LaA9kIuloa4
Report back your success.