Hello, so I am working on an Emachine that starts, I can get to the BIOS, the hard drive I already replaced and the power supply so I try to boot the comp with Windows XP, Windows Vista, and Windows 7 and all come back with the same problem, it gets to the startup screen, sometimes it will get further than others but it never finishes and then the comp shuts off, I can leave the comp on for as long as I want in the BIOS and it does not shut off, it has two sticks of RAM but it is dual channel and it seems to detect both and I ran Hirens Boot CD and it detected no memory or hard drive problems, could the problem be a faulty motherboard??? And why, or could it be the RAM or still the CPU? I am not sure which part to replace next!