First Make DOS boot disc (MS-DOS 6.22 or earlier).
Second Copy file (142355.EXE) to boot disc.
Third Run the program that was just copied to floppy (By typing 142355 at the A \ Prompt, this will self extract the bios flash program on th floppy)
Fourth Record all settings in you bios.
Fifth Insert floppy into drive and turn computer on and follow instruction when prompted.
(Driver offered by Shaun is for PB450 w/ ISA PCI combo Riser Card)
I tried this one and works fine. It will work with ISA PCI combo Riser also.