Greg put his laptop in hibernation, and when he woke up this morning, it was on. How did it come out of hibernation? Leo says it's common that if there's an update or some preset network activity (like "Wake-on-LAN"), the computer can wake up. A tremor can wake it up as well. As a rule, Leo doesn't recommend hibernation because it can confuse the operating system, causing issues when waking up. Just let it go to sleep. Users can log out, though, for security issues.