Computer turns on, not sure why, win7

So ever since I have gotten windows 7 if I turn my computer off it will not stay off. I can confirm that it is indeed powered down and it will even stay off for several hours...but at some point it turns on again. I have not figured out what exactly triggers it, but after a couple vacations I have gotten to the point where I need to physically unplug my computer to be sure that it's still off when I get back.

This is a phenomenon that is has only been present since the installation of windows 7, it did not happen when I was on windows vista.

Anyone have any idea why this would happen?

Are you certain it is powered off and not in standby mode? Is your NIC/modem configured for WOL, or is your BIOS configured to power on the system at a certain time daily?

I know I am going into "Shutdown" in the menu not standby. I have not checked WOL or BIOS settings, I will check those when I get home...but why would Bios settings change with the installation of a new OS?

Ok -- then if it's truly powered off/shutdown, then no automated tasks (windows update, AV updates, etc) should be bringing it out of 'standby'.

The installation of a new OS shouldn't (or, couldn't) change the BIOS setting(s) of your machine.

Perhaps the previous installation didn't support the full capabilities of your NIC, and thus didn't support the WOL? Then again, even if that was the case, I'm not sure how you'd be getting rogue WOL 'magic packets' broadcasted on your LAN.

Any-who, have there been any other changes, hardware or otherwise? AFAIK, the only way to turn on a computer outside of physically interacting with it is: remote mgt card (not the case here, correct?), BIOS setting to power on at a certain time daily, WOL/wake on 'ring' via a NIC or modem, or lastly to have it previously in standby/sleep mode and a program or piece of hardware bring it out of standby mode.

Is there anything else that might have changes/etc on your machine within the scope of items that could power on your computer?

Edit: Quirky, I know, but do you have a spare PSU you could try? Perhaps something weird is going on where it's mis-reading the toggle to power on? It's a stretch, but I've seen pretty strange things occur when it comes to computers...

I do have a spare PSU, I just recently upgraded and it still happens with the new PSU. It would seem like the bios option to turn on the ocmputer at a specific time would be the most likely cause, but I can't figure out why it would have gotten changed as I have never altered it.

Could be a faulty power on switch. I had this problem and it stopped when I switched cases.

Younglin said:

Could be a faulty power on switch. I had this problem and it stopped when I switched cases.

Click to expand...

Agreed. Always rule out the simplest possible causes before gutting your system, re-installing OS, or anything else drastic.

Next time you power your machine off, unplug the power switch from your motherboard headers. If it doesn't, then you've likely found the source of your problem.

TheGreySpectre said:

Anyone have any idea why this would happen?

Click to expand...

Gremlins a cat that walks across the keyboard and some bios feature set to wake on keyboard?
a dog that peed on your case , because you left em home and it shorted out the power switch.

Liquids in the power switch (see TempliNocturnus post) after a cleaning

The cmos jumper in the wrong place or loose?

i agree with the above, if its not IN the OS then the os cant effect it.
leaving any settings in the bios, including the wake back up on Power return , if you got a power surge or power cutout and that was on, including if the power plug is not stuffed into the PSU well enough.

there have been people whos Lan woke up thier machine without a magic packet, as a fluke.
.

I'm pretty sure it's possible for a scheduled task (i.e. disk defragmenter) to take the computer out of 'standby' mode and run. Can anyone else confirm this? If so, check your scheduled tasks. Something may have sneaked in there.

Kisses,
Brian

It can, yes -- Windows Update, AV updates, scans, etc. But Spectre (the OP) is fairly certain s/he is completely turning off the computer.

I think we're at either a faulty PSU, case, or BIOS setting.

Spectre, any update on your findings?