My MacBook has had song big problems, and all I can get it to do is boot up with the Mac OS X install disk, or the DVD I put ubuntu on earlier. Otherwise I get the grey screen with a folder and question mark flashing on the screen. I am unable to reinstall OS X because of the error, so we (I and a guy on this site) have worked out I need to backup my files using ubuntu, format the computer and then reinstall the OS. I don't have an external hard drive, but I found ubuntu allows me to use my iPhone in the same way. I have backed up most of my files now, but I cannot access the main folders; Desktop, Documents, Downloads, Library, Movies, Music or Pictures and I get the following message: "The Folder contents could not be displayed. You do not have the permissions necessary to view the contents of "_____". Another problem is to put these files back onto my newly formatted MacBook, I will have to access my iPhone using ubuntu, and I can't put items onto the Macintosh HD because I get the message; "Error while copying to '(name)'. The destination is read-only. How do I sort the permissions and stop it being read only??!! Please help, this is REALLY important!