Please be kind. New to OS X from years in Windows X-ile. Two stupid questions. 1. What is the best way to back up my computer (system files, applications, docs, pics, movies and all) at one time, e.g. make a carbon copy of the entire HD that could be restored after some misadventure -- is there a function within OS X or a 3rd party app that would do the trick? 2. I've installed Firefox and ClamXav and am left with .dmg files on my desktop that I don't know what to do with. I know these are disk image files, but where is the best place to put them (to get them off the desktop)?