my iMac is not booting past the grey screen(with this --->) . I am guessing that is because I did something stupid .. i changed the "Sharing & Permissions" section in my Macintosh HD Get info window. To be more specific, I changed the Everyone's permission to "no access". I tried booting with the Mac OS install disc and doing the HD recovery from the Disc Utility but it didn't changed anything. In fact there is an error every time I am trying to do "Repair Disc Permissions", while the action "Repair Disc" is completed with no problems. I don't know what to do Please help if you know what I can do to fix this!!!