My iMac (late 2009) keeps rebooting suddenly when working on it. I've noticed it more lately when I'm in Photoshop CS5. It just cuts off, screen goes black, then the white boot screen comes up. It did it 3 times last night. It's making me crazy. It's been doing this random reboot for quite a long time now. Over 2 years. It's not always when in Photoshop but I've noticed it there lately. Could it be bad RAM? Is there a certain kind I should get? I did research what type to get from the Apple website when I upgraded it to 8GB a long time ago. I've experienced this issue through different OS versions too. 10.6-10.8. I've done PRAM reset, updates etc. Nothing is fixing it. Thanks for the help.