I agree with clintfan.
Unplug your HD and connect it to the PRI_IDE1 (the blue slot) and use the upper connector of that cable for the connection CABLE-HD.
If necessary check your jumper config on the HD if it is set to Cable Select or Master.
Enter Bios, set to IDE mode, booting to CD - HD - floppy, save BIOS, exit, insert your XP CD and format your HD in setup.
Let us know if it worked.
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