Why does my Windows computer immediately turn back on after sleep/hibernate?

Question

After clicking sleep or hibernate in Windows 7, my computer loads for a while and then goes into sleep mode, but not 1 second later it powers back up. The event log has no errors and no warnings appear when it comes back out of sleep/hibernation.

Here's my system specifications:

• Asus P5KPL-VM
• Windows 7

I believe this is all that's relevant. I've installed the latest chipset drivers, but I'm unable to update my BIOS (but this is another matter; maybe because the motherboard in the V3-P5G31 bundle is different).

I've also tried turning off the "Allow this device to wake up my computer" for the network card, keyboard, and mouse -- but this makes no difference.

If flashing the BIOS is the only thing that will fix this, then I will create a new question to this effect.

Maybe I should change the suspend mode from S3 to S1?

Answer 1

Have you tried the steps listed in this page under "My computer unexpectedly wakes up from sleep"? (it's for Vista but probably applies to Win7 too)

Answer 2

To continue from Nicholaz's answer this reveals some wake events in the event log that I missed out, since they were not errors:

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To find out what caused your computer to wake from sleep, do the following:

Open Event Viewer by clicking the Start button , clicking Control Panel, clicking System and Maintenance, clicking Administrative Tools, and then double-clicking Event Viewer.‌ If you are prompted for an administrator password or confirmation, type the password or provide confirmation.

1. Expand Windows Logs, and then click System.

2. In the Actions pane, click Filter Current Log.

3. In the Filter Current Log dialog box, in the Logged list, select the time range.

4. In the Event sources list, select Power-Troubleshooter, and then click OK.

5. In Event Viewer, in the System pane, select the date and time for the event that you want to view.

6. On the General tab, view the Wake Source for the event.

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After inspecting the filtered results, I see plenty of messages like so:

The system has resumed from sleep.

Sleep Time: ‎2010‎-‎02‎-‎24T23:42:44.283678200Z
Wake Time: ‎2010‎-‎02‎-‎24T23:43:10.233041900Z

Wake Source: Device -USB Root Hub

However, I've also spotted this rather annoying "unknown source" variant:

The system has resumed from sleep.

Sleep Time: ‎2010‎-‎02‎-‎20T22:41:30.687040200Z
Wake Time: ‎2010‎-‎02‎-‎21T10:07:54.488171000Z

Wake Source: Unknown

I will update my answer if the solution is disallowing this device to wake the computer.

Update:

I have resolved my issue!

Turns out that the "USB Root Hub" source is a little misleading; it was actually both my keyboard and mouse that were waking up my computer (without being touched/pressed). The solution was to uncheck "Allow this device to wake up the computer" on both the mouse and keyboard devices (selecting them independently does not resolve the issue).

Perhaps updating my mouse/keyboard drivers will fully resolve the issue.

Answer 3

Perfrect. Thanks a lot. I had just disabled my mouse. Sadly, not allowing either mouse or keyboard to wake the PC up means I need to crawl under the desk to wake it up, but at least I can now hibernate it!! Bit of a flaw in the design. Thanks or your help.

Answer 4

You may benefit from updating your BIOS if it's not the newest version already, and/or mucking around with the BIOS settings that wake the machine up. I think you can turn off USB standby power and so on with various mainboards.

You may find that the intent of an option in poorly-documented BIOS interfaces is slightly different than the results it produces - for example, on an early build of the P8Z68-V Pro EFI image (BIOS replacement) if you turn off USB legacy keyboard and mouse support... they stop working in the EFI interface. The mainboard has no PS/2 ports. At this point there is only one way to re-enable them - clear all the settings to default with the reset button.

Fortunately the newer revisions fixed this because it was driving me loopy (the legacy USB keyboard support didn't work properly either, I couldn't use the Intel SSD firmware update CD).