i'm usining xp home and assumimg that the onboard burner is the same with xp pro.........roxio.........right click the file u wanna burn and then click send to "your cd/rw drive"..........easy as fallin off a log.........if it wasn't i would not be able to do it.
that said, i know little ( very very little) about bootable cds but i've just had a look at the link
bill posted and it looks to have all the info u need.
good luck
doddsy