I've got a Pavilion dv5 running Windows Vista Home Premium SP2. I also have my laptop connected to an external HP w1907 monitor so the screens work side-by-side (the laptop's screen is the primary screen, and it extends to the external monitor, to the right).
Usually, instead of shutting down the computer at night, I'll simply close the lid and put it to sleep. I've been doing this for a while with no effects. But all of a sudden, for the past two nights, and precisely at 3 a.m., the computer wakes up on its own. The white HP logo on the back of the laptop lid lights up, the fan whirs to life, and the external monitor turns on. And the thing is, it has now become my primary screen - so the log-in buttons are over there.
Since it's the middle of the night, I usually just turn off the external monitor to get rid of the bright light and go back to bed. At some point, the laptop goes back to sleep (because it's idle?). In the morning, when I open the lid, it wakes up as normal, although the monitors have been switched - the task bar/start menu are on the external monitor (yet the sidebar stays on the laptop's monitor for some reason) and I have to go to screen settings to swap them out.
Any ideas why a) my computer is spontaneously waking up, b) why it's doing so at 3 a.m. or c) why the monitors switch places?
OK, one possible thing - I just noticed that for the past two days there has been a "security update for Microsoft .NET Framework" that has been downloaded and installed. Today's was installed at 3:03 a.m. So perhaps this is what's doing it? Although - should it be doing this if the computer's ostensibly asleep?
Go to Control Panel / Hardware and Sound / Power Options. Then click on Advanced Power Settings. There should be a setting called Sleep with a few options under it. Set Allow Wake Timers to disabled. This will prevent any of the timed events (such as updates) to wake the laptop from sleep.