We have a 3 year old white MacBook and a 4 year old white MacBook. First out 4 year old white MacBook wouldnt turn on past the startup screen. Then turned on after letting it sit turned off for a day. Then a week later, our 3 year old white MacBook wouldn't turn on past the startup screen. What is going on? Why did this happen to both computers within a week of each other? They are used by different users. When taken to the Mac shop, they told us the insides of the computer are healthy. One of the computers he thought it might be a problem in the root directory. Any idea why they both broke at once? Is there a connection because of the age of the computers?