This may be a really lame question but I *think* I read or heard about this somewhere..... If I copy my *entire* Mac HD onto and external drive, wipe out my HD, reinstall the copied HD from the external drive back to my Mac will my Mac be the same as it was prior to erasing the HD? I mean....will my wallpaper and preferences and stuff be the same? More importantly, do I have to reinstall applications? Thanks in advance!