Hello, I recently built a new computer and for about 3 weeks it was working fine, and one day it wouldn't start up. When I hit the power switch the computer starts up for about 1-2 seconds (LED's light up, fans start, etc...), then the computer shuts off, and stays off for about 3 seconds. It turns back on, and this time it will stay on for about 10 seconds, but will not get to post. This cycle of on/off/on/off repeats until I manually remove the power. My first thought was it must be a short. So I breadboxed it by taking the mobo out of the case onto the box it came in and plugged in the CPU, 1 stick of RAM, graphics card, and the PSU. I shorted the power jumpers and it repeated the exact same process of on/off/on/off. Even with just the mobo, cpu and psu, the same problem. I removed the CMOS battery, reseated everything, and still no results After that I tried a new power supply which had no effect. So I deduced it was most likely the mobo. So I sent it back and got the new mobo and the PC worked perfectly fine. Then about 5 days later the same problem happened again. I tried to start it up and the same on/off process. I am quite confused. It works perfectly fine in all applications, then out of nowhere when it's turned off it wont start up. Also do not have another CPU to test whether or not my CPU is the problem. Edit: A thought just occurred to me. After my PC was working the first time I bought, the ASUS DVD-rom and about 5-7 days it had the problems. And when I used the next mobo, I used it again. Could the Dvd-Rom be anyway connected to this? System: Mobo - Gigabyte GA-Z68A-D3H-B3 Z68 1155 Motherboard Processor - Intel® i5 2300K RAM - G.Skill ddr3-1600 2x4GB PSU - Antec Earthwatts EA-500d 500W Power Supply Graphics - Asus ENGTX 460 1GB HD - Crucial M4 SSD 64GB ASUS DVD-Rom Thanks for any input.