well first off boot to your bios and change it to boot from cd...then bootup with the cd into the installation...you will get to a screen where you can choose the destination partition. there is an option to choose the partition then press the d to del the partition...then your drive will become unallocated space then choose to install xp on the unallocated space it will prompt you to format. choose format in ntfs and after that its just follow the prompts and watch the pretty screens. **NOTE**backup all your personal stuff and drivers to cd first. also any isp info you might need prior to wiping it out.