I'm not sure what you mean HDD partition, but assume it is your C drive. I have formatted and reinstalled 36 XP Pro machines in the past three weeks using the supplied recovery disks.
The procedure with your machine should be the same. First make sure that the PC is set to boot from the CD drive before the HDD. Check this in the bios. Insert the CD and restart. Look for the option to press any key to boot from CD at the bottom of the screen and press the spacebar. Windows setup will begin and a number of files will load. (about 5 mins) When prompted press enter to to set up WinXp. Press F8 to accept agreement. From the next set of options press esc to install a fresh copy of Windows. From the options at the bottom of the screen press D to delete the partition; Return to confirm and L to activate the deletion. Press C to create a new partion. Choose the file system you require. Fat32 or NTFS. The hard drive will be reformatted. the PC will restart at the end of the process and reinstall XP. Keep watching because you will have to answer questions from time to time about Keyboard settings, network etc.
Hope this helps.