How to Read the Wake Source Log in Event Viewer for Vista, Windows 7, and Windows 8
This will show you how to read the wake source log in the Event Viewer to see what device, task, or etc... has woke up your computer from sleep or hibernation at listed dates and times.
You must be logged in as an administrator to be able to do the steps in this tutorial.
1. Press the Windows + R keys to open the Run dialog, type eventvwr.msc, and press enter.
2. If prompted by UAC, then click on Yes (Windows 7/8) or Continue (Vista).
3. In the left pane of Event Viewer, double click on Windows Logs to expand it, click on System to select it, then right click on System and click on Filter Current Log. (see screenshot below)That's it,
4. In the Event sources drop down menu, check the Power-Troubleshooter option, and click on OK. (see screenshots below)
5. In the middle pane of Event Viewer, you will now have a list of events with date and time to select to see the Wake Source of. (see screenshot below)
NOTE: For example, the HID-compliant Bluetooth Mouse was what woke my computer last at the selected event date and time.
6. When finished, close Event Viewer.