Hi guys! I've recently bought an msi Geforce gtx 960, and call me stupid but I need a hand installing it, I've put it into my computer and when I turn it on its telling me to plug in my pcie power cable, (my last graphics card didn't have one) so I'm stuck as to where I plug it into on my motherboard, I got the 8 pin port on my graphics card and it came with an 8 pin - 6 pin adaptor, but that's as far as I can get lol, also my motherboard is an msi h81m-e34, anybody able to help me would be much appreciated, thanks