Try this first:
- Start an elevated command prompt. (Start, run, type
cmd. Cmd.exe should appear in the list. Right click on it and select 'run as administrator'.
- In the large black screen type
With a bit of luck this will already show you the timer which is set to wake windows.
If it does not list anything (such as in the example above) proceed to check the event log.
- Go to [start] [run] and type
- Open windows log
There are a lot of entries here. Lets limit our view with a right click on 'system' and selecting Filter Current Log [SIC].
We are looking for power related items, so go to
Event sources and select
Power-Troubleshooter and click on [OK]
The view should now contain a lot less items. If you are lucky it contains a line such as:
The system has resumed from sleep
Sleep time 2012-10-21-typeitallovermeh
Wake time 2012-10-21-yayaydydyay
Wake source: Device-HID-compliant mouse
If you do not have a cat which plays with your mouse you will likely find another reason here. E.g. wake on LAN activity.
Once you know the reason you can counter it. Usually by going to the device manager and removing the 'allow this device to wake the computer`.
Other likely candidates not solved via the device manager are:
- Windows update. (It can be configured update your computer automatically. It can boot the laptop do do this, so check this option first. Especially if it happens at 3AM which is its default time).
- The BIOS. Some include an option to wake the computer at a specific time. This seems an option which is rarely present on frugal laptop BIOSses, but you will find it in allmost all server and workstations.