My friend and I are trying to get a homebuilt system up and running from spare parts he has lying around from a recent rebuild he did on another computer. Long story short, we cant get the mobo to power up. Everything seems to be plugged in except the 4 slot connector on the mobo (from what I have gathered, it is 4pin atx). There are a few cables that are 6 pin males running off the psu that are left over that are labeled PCI-E (which I assume are to be used on pci slot devices such as the video card, and not the mobo). There is also an 8 pin cable, which I can't seem to figure out what it is from the website I was looking at. (see below). We have some people saying that the 6 pin pci e can be used to power the 4 pin atx. From what I have found on the internets, you are not able to convert 6 pin pci-e to 4 pin atx. The questions I have to ask at this point is....
1. Is there a way to convert 6 pin pci-e to 4 pin atx?
2. Is there another cable I am missing that can be converted to 4 pin?
Below is a diagram of the 8 pin cable I can't figure out.