I have a NVIDIA GeForce 9800 GT that has been having problems. Once I put the graphics and boot up the computer sometimes the computer will fully boot up, while other times the computer fans won't run properly and my screen will stay black (even though the light to say it is on is green). And even when the computer and screen fully turns on there are weird vertical lines across the screen in some areas. I don't know what the problem is but I think it may have to do with either my OS being Windows 10 and the graphics card says Windows 7 only, or that the extra power supply cords aren't connected properly.