I just built a new PC and it won't stay shut off! I'll turn it on like normal and it POSTs and boots to windows 7, but when i shut it down, 5 seconds later it will reboot itself. EVERY time, never fails. Last night it rebooted a couple of times too, but i wonder if it was just updating itself or something because today it was fine about staying on. add on speaker makes no beeps. Here are my relevant specs...
Unplug and replug everything back in.
Exchange power supplies with a known working one.
Ensure that all motherboard standoffs are in correct places and only the correct places.
Remove GPU and use IGP.
Manually short mobo power button pins and shut down without that cable plugged in.
Exchange RAM sticks with known working sticks/try different slots.
Ensure that BIOS/Device manager power management settings don't have "WOL" settings enabled.
Changed power cable.
Make sure power button fully engages and disengages.
I got it figured out! Finally! I cleared the cmos again for like a minute, unplugged everything, plugged in the components one by one, did another restore, and it now it doesnt turn itself back on anymore. I dont get it, but hey whatever works lol.