My computer wakes up from standby in the middle of the night and doesn't want to remain standby

I had a similar problem - but the PC resumed just after 10 seconds!

I checked the Wake On Lan thing, control-panel settings, device settings and what else I found, but nothing worked.

So I got curious, what caused the wake - and found the pretty handy Microsoft commandline tool powercfg.exe (comes with Windows).

Wait for the computer to resume unexpectedly and start

cmd

with administrator rights. Type

powercfg /lastwake

and it displays the hardware responsible for the wake.

In my case it didn't show any device responsible. But there's is another command

powercfg /waketimers

It shows all processes which registered resume-timers. In my case the Samsung hard disk tool "Magician" was responsible for it - uninstalled it and now everything is working as expected again!

I hope this helps you!

Type Mouse into the start menu search box, or the Control Panel search box, and then open up the Mouse Properties panel. Find the Hardware tab, select your mouse in the list, and then click the Properties button.

You’ll have to click the Change settings button before you can see the Power Management tab…

And now, you can uncheck the box from Allow this device to wake the computer.

That’s all there is to it.

Source. Written for Windows 7, should work in Windows 8.