Update (12/18/2013): I finally replaced the Video Graphic Card with my old stock (Gigabyte nVidia GTS 250). The issue seems solved this time. My Zotac nVidia 650 Ti the culprits, I just bought this card 6 months ago, I should get the replacement.
Update (12/16/2013): After long trial and error (did clean install also), I found out the BSOD happens after NVIDIA Driver installed. Not sure why, but hopefully this is not related to PSU malfunction. Rolling back to old driver now.
Update (12/14/2013): After applied some updates for Win 8.1 pro last night, I’m experiencing the random restart again. The problem seems solved with upgrade the Chipset and SATA driver. Haven’t got any unexpected reboot in two days.
I made upgrade to Windows 8.1 last week. But since then, the Windows keep restarting randomly in time. I checked the log and it shown “kernel-power” issue. I found no malfunction in BIOS, hardwares, and config. But then I suspect the power settings, I figured out on some forums, the “fast-startup” could also be a problem. I decided to deactivate it.
It’s been 24 hours and I don’t get any unexpected reboot again.