GA-B75M-D3H: Turns itself ON every day

[Photon]

Built this sytem about two years ago:  GA-B75M-D3H, BIOS F12, Core i7-2600, 8GB DDR3-1333.  Used as main system for about a year (high usage every day), then built a new system (GA-Z87M-D3H) so this one became secondary system (only occasional use), but continued to work fine.

But now, this system has begun to TURN ITSELF ON every (early) morning.  I have disabled all wake features on network adaptor (WOL, etc.) in Windows Device manager, and even disconnected the Ethernet cable, so it isn't network related.  I have disabled automatic startup settings in BIOS, with no change.  I even disabled boot to HD in BIOS, but it still turns itself on every morning (and now of course just gives a message that no boot device can be found).  When I re-enable HD boot in BIOS, it still turns itself on every morning and boots normally.  [The boot is normal--the turning itself on is NOT.]

The last time I used this system before the problem began, about the only thing I did on it was update Firefox (did this a test, before updating Firefox on main system).  Even if the Firefox update contained some malware, how could it cause the system to turn itself on, even with HD and network disconnected?

Any help, please?

[dmdilks]

Have you tried to clear the cmos and pull the battery. Let that sit for a couple hours.

Put the battery back in unclear the cmos go in set it to default setting then set the time and date. Then let it sit and see what happens.

[Photon]

Well, this is interesting.  Today, the computer did not turn itself on.  Too early to tell whether the issue has been addressed, but will watch it for a time to see.

On my (so-called) desktop systems (actually, under-desk tower systems), I use wireless USB mouse, but PS/2 keyboard.  The reason is that I love to be able to turn the system on by just touching a key on the keyboard, and Wake-on-Keyboard only works with PS/2 keyboards, not with USB keyboards.  So, Wake-on-Keyboard is one feature that I hadn't turned off.  But the keyboard is on a drawer which slides under the desk when not in use, and so somewhat protected (as from falling objects, for example); and, there is no one here that would be pressing keys.  So, I didn't suspect that feature.

Yesterday, I turned that feature off.  And, while in the BIOS Power tab, I saw something else enabled, which is labeled High-Precision Timer, which I turned off as well.  Can anyone say what that timer is for?  And, if the issue proves to be solved, which of these two features would you suspect?

[autotech]

 High-Precision Timer allows you to set a time in which to turn your computer on each day as say 8am or 12 noon and so on.

[Photon]

High-Precision Timer allows you to set a time in which to turn your computer on each day as say 8am or 12 noon and so on.

In the BIOS Power tab, there is a section for that, with fields for Day, Hour, Minute, etc.  The High-Precision Timer field has only Enable/Disable, and is in a different section of the Power tab, so I don't think it's related.

[Photon]

So after 11 consecutive days without self turn-on, yesterday I re-enabled Wake-on-Keyboard in BIOS, and sure enough, this morning the computer turned itself on.  This makes me sad, as I really love the ability to turn on by pressing a key.

Today, I changed the BIOS Wake-on-Keyboard setting from "any key" to "keyboard 98", to see if that would alleviate the issue, while still allowing turn on by keyboard.

Does anyone know the difference between these two settings?  I suspect that it just effects which keys will be accepted.  I also suspect that it won't prevent the problem; will find that out tomorrow.

Any further info as to what "High-Precision Event Timer" does?