I had the same problem on my XPS. It was starting precisely at 0837ET almost every morning. I later found that Media Center was bringing the laptop out of hibernation for an update. I found it in the Event Viewer: Event Viewer (local), Applications and Services, Media Center, in Events I found the earliest entry for that day (which was 0839), clicked on it and found the scheduled start at 08:37:34 in the General tab below it. Now all I have to do is change the time. I hope this helps.