first go by removing/formatting the partitions used by Fedora Core I.
besides, did you try booting from your XP cd and executing the two commands:
fixmbr & fixboot (in Recovery Console)
I think they should do the job.
also, since you have Service Pack 2 installed, that's why your Windows XP cd is not working. You will have to create a slipstream cd of Windows XP with Service Pack 2 in order to be able to work with it.
go to
http://www.nliteos.com/ and download Nuhi's software (nLite) for slipstreaming Windows XP cd with Service Pack 2.