I've looked around for a good answer to this, but haven't been able to find it. It might be because I'm not smart enough to figure it out. . I have a February 2008 mac that I'd like to get rid of. I lost the start-up disk. I was originally going to give it to my cousin, so I went to the genius bar and asked him to re-install the OS, or in some other way restart the system. They did that. Now, my cousin doesn't want it so I'm selling it. To prep my computer for someone I don't know, I ran the thing in disk utility that re-wrote over my empty hard-drive space 7 times. I wanted to do a double check so I installed MacKeeper and it's finding all these files that were apparently deleted. Was the data on my hard drive actually deleted? Can anyone access the things from my old account really easily?