About a month ago this message appeared on the screen at start up "Operating system not found on any device". I shut the tower down and tried again and the same message appeared and then retried and everything booted up fine. Now the message has come up again and I can't get the operating system to come on at all. I was going to try and start it in safe mode but I can't even get to that. I was going to get all of my info off the HD so that I could redo my drive but now I can't even get to that. HELP. Is there anyway to get my stuff off of there so that I can start over fresh.