Why does my computer wake up?

It is amazing to think that all of these things have happened to me since I started using Windows 7! I hope some ideas here help you solve your mysterious computer startups.

Mouse & Keyboard is Waking your Computer

Windows 7 has an annoying habit of starting up from a sleep or standby mode without any obvious reason. This list can hep you track down the cause, and how to stop it.

First, test to see if moving your mouse or hitting a keyboard key is the cause of the startup.  For some stupid reason, every time you install a new mouse or keyboard in Win7, the default setting is to allow it to "wake from sleep".  If this is the cause of the problem follow the steps below to turn it off.

1. Click on the Start button.
2. In the search box, type "device manager" and click on exactly that name in the list.
3. When Device Manager opens, click on the arrow beside Mice (or Keyboards).
4. Double click on your mouse and select Properties.
5. When the device window opens, click the Power Management tab.
6. Clear the checkbox beside "Allow this device to wake the computer."
7. Click OK, and close the Device Manager.

Network Card wakes your Computer

The most common cause of a computer waking from sleep mode is the network card.  Follow the instructions above, but select "Network Adapters" instead of Mice.  Double click on your network card and proceed to the Power Management tab.

If the checkbox is already clear, then you might check a few other devices to see if they have a Power Management settings that is checked. If hardward devices are not causing the problem, then it must be an application (program).

Advanced Power Settings can allow your Computer to Wake

Windows 7 computers have terrific power options that allow you to put your computer into a standby mode to save power and enable fast restarts. Checking the Windows power settings - they may have been changed by recently installed software.

1. Click on the Start button.
2. Type "Power Options" in the search box and select it. (Or click "Control Panel", then "System & Security", then "Power Options").
3. Select "Change plan settings" beside your power plan.
4. At the bottom of the next page, select "Change advanced power settings". This windows contains many useful settings.
5. Click on the plus sign beside "Sleep" and again beside "Allow wake timers". If either are set to "enable", click on the setting and select "disable". Click OK and exit power plan windows.

Automatic Switch from Sleep to Hibernate Mode

Does your computer "wake" from sleep and proceed to do a hibernate "save" to disk, then shut down again (in Hibernate mode, which uses no power and restores your system as it was when it went into Sleep mode). The Advanced Power settings is where you change the time before the computer automatically moves from sleep mode into hibernate mode - the default settings is too short. Under Sleep is a setting "Hibernate after", I set it to 2880 minutes (2 days) on battery and 7200 minutes (5 days) when plugged in. Another mystery startup solved!

Programs that Wake your Computer

As a last resort, you may use a small Windows tool called powercfg to discover what is waking your computer.

1. Click the Start button.
2. Type cmd in the Search box, and a special window will open with a "command prompt" (>) and a blinking cursor.
3. Type powercfg -devicequery wake_armed (exactly)
   Lists all devices and programs that can wake the computer. Hopefully the list was blank. If not, check it out. (You're on your own here.)
4. Type exit to close the window (or click on the X button).

If you know of other solutions, please let me know. This library is here to help others - with the help of Google.com that likely brought you here!