My Mac book kept restarting over and over, it would stay on the grey screen with the spinning wheel going and going. It started after I deleted some files, I dont know if I accidentally deleted something I wasnt suppose too. So I reinstalled the mac os x that originally came with it, it seems to be working but my disk space is almost full. I believe that the other system is still installed in my hard drive in my program file it shows old system. How do I go by fixing it or uninstalling the new mac os so I can go back to my old version and how do I fix the restarting problem. Can you please help me out on how to fix this problem.