I'm relatively new to the world of Mac. I was a long time PC user and decided I needed a change about 6 months ago. I am now using a MBP, but am a little confused. In the last two days, I've gotten 4 messages upon booting the machine. It says, "You must restart your computer. Press and hold the power button" or something along those lines. The text is displayed over an ominous-looking gray screen. Does anyone know what this means? It's getting rather annoying and I'm worried that I'm going to lose the information on my hard drive. What is causing this? How can I fix it? I would appreciate any help. Thanks guys.