Hey folks. Thanks in advance for any help. Here are my symptoms: Was watching a 720p HD movie on a plane. Movie starts to freeze up. I can move the mouse but the rest of the computer is unresponsive. I force shut down by holding the power button. Upon restart, all seems well, I login but computer quickly becomes unresponsive again. I force shut down again. Next restart is over 10 minutes. Gets to login screen but can't login. I boot from install disk and run HD repair. It finds some problems and repairs them. Reboot. Same symptoms. I decided it is the HD and archive and install. Install fails. I wipe the HD cleaned and reinstall osx. All seems fine as I go through set up and login in. A few minutes later same unresponsiveness. So finally I did what I shouldve done awhile ago which is swap my current hd with my old one. I do and the computer runs fine! I'm at my wits end. Just so everyone knows, the day before all these symptoms started I swapped my stock 2x1gb ram for 2x4gb ram. I originally thought that was the problem but I've had my original ram in since I've been trying to diagnose and it's made no difference. Once again, thanks for any help.