our school pcs use windows 98se and even if you do spend an hour downloading ans installing the drivers for pen usb drives to work they never do and basically everyone i know doesent have a zip drive
sometimes it even depends on the batch of mobo's, some I've had to deal with were a but fussy about booting off of usb floppy until after they'd been flashed. Not so helpful if you're trying to flash them from a floppy disk. but yeah, most modern mobo's will boot from usb floppy. (or indeed memory stick, or possibly even an SD card in a usb reader...).