Need program pointers

Hey all! I'm looking for some program recommendation and locations pointers. Both for MS-dos. First, a good secure delete program. These I know exists, which are good? Second, I don't know if this exists. I've never heard of one but it should! I want a program to go through a DOS hard drive and zero out all the unused sectors. It would also be nice if it zero'ed the tailing disk block after the end of a file. Suggestions? Thanks, Don -- America - a country so rich and so strong we can reward the lazy and punish the productive and still survive (so far) Don Melvin storm@ssnet.com finger for PGP key.