Pc resarts 4seconds after shutdown. seems motherboard related!! (win 8.1)

[Pantelhs Xirouc]

hello forum. i am facing the following problem, which i will try to explain in as much detail as possible
i have a mini ITX based system (Asrock H61MV) the mobo is brand new, but i had win 8,1 already installed on an SSD. when i first connected the SSD on the mobo, everything worked perfect. then after some time (and some updates) the pc was unable to shut down.
AFTER the "shuting down" logo disapear the screen backlight would stay on (my LCD is powered from my PSU) and the systems fan would keep turning. (BUT when i installed another HDD, i noticed that it would stop spining). I always had to force close the pc, by holding the power button 5 seconds....

• 
  I tried another PSU, but the problem remained exactly the same.
  I tried another HDD with a fresh win 8.1 install, and the probelm remaind the same.
  THEN i removed the CMOS battery, and left the mobo without power for 5 minutes.

After i turned it back on, the PC can now shut down. BUT it turns back on, 3-4 seconds after it closes... the probelm exists in both the SSD and the HDD...

any advice how i should move? since the HDD stops spining, is it safe to just "unplug" the system, every time after it shuts off?

P.S : if its powered off and unpluged, and then i plug it in, it does not power on, untill i press the button.

 

[Outlander_04]

Update the BIOS

Set the BIOS to halt on all errors

and then if that doesnt work try changing the power schemes in win 8 . I have seen similar behaviour with an asrock board and win 8 and I have no idea what fixed it , but those were things I did and eventually it started behaving as it should

 

[Pantelhs Xirouc]

Update the BIOS

Set the BIOS to halt on all errors

It has the lates bios installed OEM.. i have disabled the "reset on system crash" in windows, but i cant seem to be able to find a simmilar option in bios... although i remember older mobos have it!

 

[Pantelhs Xirouc]

well some more info... every time i reset the bios, the pc starts behaving fine. but after i remove the power cord (i have to), the problems will start again...