Looking for Secure Delete Freeware

I have several personal files on my work laptop. O/S is XP Home Edition. I’ll be leaving my company soon. I need to permanently delete some files before I turn it in. Anyone have any ideas. Would like some recommendations on Freeware. Otherwise will take suggestions on a retail product. I’m looking for a Freeware file shredder. I know how to delete files and empty a recycle bin.