I spent almost a week trying to figure out why my computer shutting down randomly instantly, as if someone pulled the power cord. It can last for up to 2 hours or 2 seconds after pressing the power button. I built this gaming rig 1.5 year ago, it can still easily runs the most demanding games out there. I don't want to waste money replacing parts unless I'm absolutely sure. So I need everyone's opinions. First I thought it was software related error, so I went into cmos mode, and it still shutting down, so I figured it most like hardware related. I unplugged all hard drives, dvd drive, and tried again just to be really sure it's hardware, still shuts down. I thought maybe if the cpu was overheat, so I let it sit in cmos mode and watch the cpu temp, it was around 39-45C, that's normal. I bought a brand new power supply and it still shuts down randomly!!! I took out all memory sticks but 1 and switch in between and took out the graphic card too, and still it shuts down!!! I checked all the capacitors in my motherboard, blow all the dusts, checked for cracks, and nothing out of the ordinary. My question is wth is wrong with my computer? Help!!!!!!!!!!!!!! I probably already answered my question, that it's probably the motherboard, but I want to be sure if there's something else.