Computer Turns On by Itself - Windows 7 x64

I never use sleep or hibernate mode, I always shut down. Sometime between 10 minutes and one hour after shutting down the computer starts up again.

Computer:
Intel i5-2500k
ASRock Z68 Extreme4 Gen3 (Bios P2.20 Latest)
16GB 1600 RAM
OCZ Vertex 3 120GB
Hitachi 1TB drive
HD6850 Graphics

Built the machine 6 months ago, recently had an issue of the system locking up. Isolated the issue as OS corruption. I restored from a Windows backup from one month prior, issue went away, but this new issue showed up. While I was debugging that issue I flashed the latest firmware to the Motherboard. Also, I doubt it's the power button since the issue started after a software change.

BIOS Settings:
CPU Configuration
Enhanced Halt State (C1E): Enabled
CPU C3 State Support: Enabled
CPU C6 State Support: Enabled
Package C State Support: Auto

Southbridge Configuration
Deep Sleep: Enabled in S5 (I have tried disabling this also)
Restore on AC Power Loss: Power Off

ACPI Configuration
Suspend to RAM: Disabled

Boot
Boot from onboard Lan: Disabled

Windows Settings:
Device Manager -> Network Card -> Power Management
Allow this device to wake computer: Unchecked


I saw this post and tried to follow as many suggestions as possible before starting a new thread. One thing is the task scheduler. I'm not sure what to look for in the scheduler which would allow a task to wake the machine. At least I've never heard of a task doing that before.


Any suggestions what else to look at?

Thanks in advance

Paul

For me personally, when flashing the BIOS, it's like changing the CPU, when changing the CPU I preferr to do a complete fresh clean install. Thus to insure of no hidden hickups that may occur some where down the line. Not saying that you wont get one but the odds are much better that you wont when doing a fresh clean install.

I use Acronis to create a full image backup on a weekly basis and I have it set to wakeup from sleep and not allow sleep while performing the backup so it could be some software that is used for maintenance. IE Antivirus scans, Windows Defender scans, Defrag.....

I am really at a loss about this issue. I have checked everything I can think of. Still booting by itself.

Format the drive and do a clean install of Windows.

I have several development environments, VPNs, Databases and other software installed. It would take me probably 4-5 days to get things back the way I need them. I just can't go through another full Windows re-install.

And just for the record I have done the following debug steps:

1. Unplugged the network cable after a shutdown. Still booted.
2. Checked every job in the Task Scheduler library for the option "Wake the computer to run this task" set. None were checked.
3. Re-installed all motherboard drivers with a reboot when it was requested by the installer. (Downloaded and installed the most recent drivers from Intel).
4. Tried switching the reset and power buttons to make sure it's not the button shorting out.
5. Checked the device manager for any devices with a Power Management option and made sure the device did not have "Allow this device to wake the computer" option checked. The only one that had the option was the Broadcom Netlink driver.

So the question stands:

Besides Wake-on-Lan and Scheduled tasks in Windows, what can make a computer boot itself?

If I can get an answer to that question, I know the next place to look.

Hi Picasso

Your motherboard's lastest Bios update (2.2) has has Dehumidifier function.. which as per the manufacturer

Dehumidifier
"Users may prevent motherboard damages due to dampness by enabling “Dehumidifier Function”. When enabling Dehumidifier Function, the computer will power on automatically to dehumidify the system after entering S4/S5 state"


I do have a feeling this got on somehow .... (its disabled by default).... Try disabling this and see if it works..

Maybe i missed where you answered this but...

Have you looked in the Events log to see if anything is there showing why the PC re-started ?

centaur78 said:

Hi Picasso

Your motherboard's lastest Bios update (2.2) has has Dehumidifier function.. which as per the manufacturer

Dehumidifier
"Users may prevent motherboard damages due to dampness by enabling “Dehumidifier Function”. When enabling Dehumidifier Function, the computer will power on automatically to dehumidify the system after entering S4/S5 state"


I do have a feeling this got on somehow .... (its disabled by default).... Try disabling this and see if it works..

Let me preface this by saying that I checked the BIOS settings probably 20-25 times one by one. Each time saying to myself, "Look it over like this is the first time."

I misread the Dehumidifier setting. Every time. I didn't realize that this setting turned the MACHINE ON!

So, in essence what I am saying is that I'm an idiot.

Thanks Centaur78. If you hadn't pointed it out, I probably would have kept missing that for a year. I happen to live in Tokyo and the summer heat sucks big time, esp in a room with a hot CPU running all night with no air conditioning.

Now if I could only figure out when the setting changed. There's no way that a BIOS firmware update would default to on, so I must have turned it on myself, I just don't remember.