the "make boot floppy" option in Add/Remove Programs; there's a tab.
W2K sounds like red herring - for your purpose, no? Who cares if it usually runs W2K (and has no 'DOS') if you only need to flash BIOS. 'Course if no available machine has <W2K on it.. (Like even at the drugstore? ;-)
Then of course - Scott's link has prolly already gotten you an image.
Ashton