I've recently been having issues with my power cable. When plugging it in, it won't charge. So I figure the adapter needs to be replaced. I had my iphone charging today, and for whatever reason my phone would not back up. It said there was another souce already open and syncing, or something to that effect. So I unplugged my phone, and deleted some old movie files with CLEAN MY MAC program, and went to restart my computer.   Since then, I've been stuck on the...