How did you originally format xp?
Is this a legit copy of XP your trying to install or a burned copy?
Is the CD clean of all lint/dust?
Take the CD out, ensure it's clean, enter the BIOS and make sure CD is set to first boot
Replace CD and try booting with it again
Remember to delete partition and format with normal ntfs, not quick
If that doesn't work, you may have to try a third party boot disk to delete partition
Do you have a floppy drive?
You can try a 98se boot disk, if no floppy you can create a boot image
Here's more instructions
http://www.onecomputerguy.com/install/fdisk.htmDon't forget to fix the "mbr" also from the guide