I have the macbook pro 13" unibody OS 10.6.4 I usually don't turn it off, I close the lid and it goes to sleep. Well last night I closed the lid, put it away, and I woke up this morning to see that it had completely shut off. So I turned it on again, used it for a few hours, and closed the lid and put it back once more for maybe 30-45 mins. I took it out again to find out that it had once again shut down. Both times it completely lost the wifi info and I had to reconnect manually and add the key again. I usually keep it plugged in, so battery wouldn't be an issue. Any ideas as to what's causing this problem?