Consider this: If you use a cracked version of Rundelete, you have no idea if the crack author altered the "shredding" algorithm. Perhaps the crack only pretends to overwrite the data but actually leaves it intact, or worse, sends a copy to a remote server.
When you append "hot" to "registration key," you are looking for a key that has not yet been blacklisted by the developer's servers. In the cracker subculture, keys go "cold" quickly. Developers use revocation lists to disable leaked serials. rundelete registration key hot