I have a mbp, with a guest account and a user account. I'm selling the computer (in order to get the new one), and I want to make sure that EVERYTHING is erased (browsing history, downloads, caches, movie downloads, music, etc etc). As we all know, just placing it in the recycle bin and emptying it doesn't delete the files. So, what is the procedure to do this? Again, I want to erase EVERYTHING. Basically, I want the person who buys this computer to boot up as if it were the first time the computer was ever turned on before. Sorry if this has been posted, but I did do a search before writing the thread. Thanks mac users!