I leave my MacBook on all the time. Overnight, it doesn't go to sleep, I set it to just turn the screen off. So this isn't a sleep issue, just to be clear. Sometimes, when I go back on the computer in the morning, the computer seems to choke on everything - anything I do gets me a beachball (click OK on the "you have been disconnected from AIM" dialog? Beachball. Trying to open a window in an app? Beachball. Trying to open a menu? Beachball). After a few minutes, the computer suddenly fasttracks through everything I've tried to do, and it's fine again. This happened a few times, but today was the worst - the computer just froze. I can move the mouse, but that's it. The GUI is totally unresponsive. I had to hard reboot to get out. Anyone know what's going on from those symptoms? Is my HD failing? I have recently upgraded my RAM. Can that be it? The Apple Hardware Test says there's no problems. EDIT: Just remember that a common factor in many of those occurrences is that I have been disconnected from the internet sometime during the night. But that doesn't make sense for the OS to literally grind to a stop just because it's disconnected from the 'net. Especially since it's been awake all along and can handle it a long time ago (during the night) instead of waiting for me to come back on.