I had some problems a few months ago with spontaneous shutdown of my Macbook. That was cured with a logic board replacement. My 60 Gig hard drive is filling up and so I have been using Whatsize to find and delete files and programs that I don't want or need any longer. In the course of doing this I have found some rather large swap files and a sleepimage file (see attached). I wonder if these are left over from the shutdown issues I had and if I could safely delete them. Advice?