How much do you need to get rid of it? To completely remove data such that it cannot be restored by forensic data retrieval software, you'll need to do a low level format. Otherwise just reinstall XP or use one of your hard drive manufacturer's utilities.
Barton 2500+, 512MB Corsair Platinum XMS 3200 CL2, Radeon 9700, WD Raptor 10,000 rpm S-ATA HDD, Asus A7V600, Enermax 460W SilentPlus PSU.