ok, im a lil confused, are you trying to boot from xp cd to reapair/modify/add files ?
going into bios:
upon spash screen, hit, "Del" F2 depending on mainboard, but it should tell you, on bottom left hand side of screen during boot up, to hit Example : ESC to enter bios.
hope this helps.
Let us know what you are trying to do & we will help as much as we can.
then change boot order to boot to Cdrom first,then hd then floppy