Summary: That is because the 24-pin harness isn't connected right and so it doesn't make solid connection with the motherboard thereby making it inoperable. Ordered a replacement will update if this one works.
Summary: When i first recieved it back in november or december, it gave me some trouble after i installed it and tried turning the computer on. It wasnt supplying power to the motherboard. i disconnected and reconnected it thinking it was a connection problem. after a few attempts it started working fine.
Summary: Recieved this item quickly so good job on amazon's part. Read installation manual and prepped the case for installation. Installed the new unit and powered on. Booted fine so shutdown and installed the new video card then repowered, While installing drivers suddenly PC shutdown.