I have a 13' macbook pro (2009). In the past year, it keeps having problems. Basically, it freezes and won't boot-up. However, this could always be fixed via boot into safe mode, or reinstalling the OS. Previous hardware diagnostics never detected hardware failure. I've never touched anything inside the computer including hard disk, RAM, battery and everything else. Today, it froze as it did before, and I could not manage to boot it by ANY means. After I press the power button, no grey screen, no apple, it just froze on a blue screen. I was running okay before it froze up. I had safari and skype running and nothing else. The computer did not response to any of the startup key combinations (I've tried every single one that I could find online, including resetting NVRAM and SMC). It won't boot from installation disc, and, since startup keys did not work, I could not eject the disc. One strange thing is that when the computer froze at the blue screen, pressing power button will IMMEDIATELY shut down everything. That is, I did not have to hold the power button to shut it down, it seemed as if all the power was unplugged at once. Could someone tell me, what could possibly be the problem? Thank you very much!!!