When I first got my Mac in August, it had some problems. I was on and off the phone with Apple tech support for a good month before we fixed the issue. Now, everything's fine, but I have a folder on my primary HD called "previous systems" and I can't remember if it was there before or not. The folder's contents add up to like 2 or 3 gigs, and I am nervous to just delete it, but wonder if I need it. It has a full lineup of recognizable folders, like Applications, Library, etc, as if it is a backup of some sort. Is this a normal nessesary thing to have on a Mac HD? Thanks in advance.