Have you checked if the jumpers were correct on the cd-rom?
Also the lens is clean and the xp disk is clean?
Was windows installed on this machine previously? or a clean install?
Try making boot floppy's for xp, the boot disks.
http://www.bootdisk.com/
Get 4 disks and grab the windows xp boot images from that site.
Make sure you have it switch to boot from floppy first.