I am going to be selling my trusty 12" PowerBook G4 to a friend soon, and putting the money I get from that towards a last revision 15" PowerBook G4. After I transfer my data from the 12" to the 15", I want to completely and securely erase my hard drive. The thing is, I don't know how to do this! I've never formatted/erased a hard drive before. So, how do I do it? Thank you!