My Dell Studio 15z (Windows 7) has been waking up by itself at night for some reason which I haven’t determined yet. It’s not waking for virus scans. The bad part is it doesn’t shut itself back down. The other night I had it hibernated and it was not plugged in. When I got up in the morning, the battery was dead.
After some searching, I found that it’s a Windows 7 thing. There’s two settings which will allow Windows to wake up your machine if there’s a scheduled task. YMMV - I don’t know if Dell defaults these settings differently from other manufacturers. Here’s the solution from http://en.community.dell.com/support-forums/laptop/f/3518/t/19307826.aspx. In a nutshell:
- Left Click on the power icon at the bottom right of your start bar
- Click on “More Power Options” (or just search for “power options” on your start bar)
- Click on “Change plan settings” on either Balanced or Power Saver (depending on which one you use)
- Click on “Change advanced power settings”
- Once your Power options panel opens, scroll down and select “Sleep”
- Click on “Allow Wake Timers” and then click on “Enable” and scroll down to select it as “Disable” (there’s one for “plugged in” and one for “battery”)