i was just installing that sw update, and it failed.Safari won't load, so i just restart it, then it shows apple logo with a spinning gear. RIGHT AFTER APPLE LOGO TURNS INTO PROHIBITORY SIGN(BROKEN FOLDER ICON) STILL HAVE THE SPINNING GEAR. THEN I TRY TO BOOT INTO SAFE MODE, IT'S NOT WORKING, AND STILL THE SAME. I DON'T HAVE TIME MACHINE BACKUP. PLEASE HELP, WHAT I'M GONNA DO, PLEASE HELP!