You downloaded the wrong boot disk......
Download the (XP BOOT DISK) thats the one you need
Once you downloaded the disc follow my last set of directions and once you've done that
it will say please put in the drive letter and press enter.
this an example.... D:\setup and then you press enter.
What ever your drive letter is that you have the dell xp cd put in that letter. if you need help go to my computer and take note which drive has your dell xp cd.
Come back if you have any more questions.