Asus P4BP-MX - Manual (Page 38)

2-6 Chapter 2: BIOS Setup
7. The utility starts to program the new BIOS information into the Flash ROM. The
boot block is updated automatically only when necessary. When the
programming is done, the message “Flashed Successfully” appears.
8. Follow the succeeding screen instructions to continue.
DO NOT turn off the system while updating the BIOS. This may cause boot
problems. Just repeat the process, and if the problem persists, load the original
BIOS file you saved to the boot disk. If the Flash Memory Writer utility is not
able to successfully update a complete BIOS file, call the ASUS service center
for support.