|"but when i insert the reformat disc. it says it is corrupted"|
What format disk are you inserting?
You can format your disk during Windows installation, so you do not really need any additional disks.
You can insert your Windows XP disk, go through the options, and after you are asked to press F8 to agree to terms and conditions, you will be shown a list of available hard drives, select the drive you want to put Windows on, and either format it or just delete the partition.