Hi I recently purchased a used Macbook Air, late 2010 model. I had deleted the old user (I selected safely remove user)..and I reinstalled Lion hoping it would wipe everything out, but everything was still the same and I noticed that there's still stuff taking up hard drive space. I have no music, no movies, and literally one picture in my users folder. The only Application I had installed onto the computer is Chrome and Microsoft Silverlight for Netflix. Is there a way I can start with a clean slate? I don't mind starting over since there's nothing on this computer anyway.