I tried everything I found posted and nothing worked but: Here is what seems to have finally worked for me. I erased my hard drive using recovery. I was able to connect through wifi and boot from my laptop, then used the migrate tool to move my data over. I uninstalled Norton 360 since so many think that was the problem. I restarted afterwards and everything was fine. I changed my option to update automatically to manual updating. I haven't done a complete shut down yet but hoping all will go well.