The Computer I built for my cousin broken down a couple of days ago. He asked me to help him fix the computer. His computer was taken to my house this morning. I pressed the power button. The fans could run, though the computer wouldn't start up. I took it apart and switched almost every single component in the chassis except the PSU because I leaned to believe the motherboard was broken. The problem remained. At last, I pulled my PSU out of my PC and connected it to his motherboard. Then amazing happened. It worked! I put his PSU in my computer then my computer wouldn't work. I finally realized that the PSU was broken. And guess what? It's an Antec NeoECO 400 Watter which have been severing the i5 2300 + GTS450 rig for nearly 9 months. My cousin couldn't find the receipt and packing box for the PSU. Thankfully, 360buy (where I brought the PSU and other components of his computer) has accepted my request for repair. It probably will take quite a while before they send the PSU back. So I gave my PSU to my cousin and currently I'm using a junk PSU.