I am trying to upgrade (marginally) a Lenovo H50 by changing the video card. Not for gaming on this mini rig, just trying to get a better video watching system. I know that you need to change the power supply first. I bought a new 400w and a 14 pin converter but when I start the computer, the fan spins for a half second and it stops. I bought a different 14 pin converter and tried a different known good power supply and the same thing happens. Any ideas as to what else I can do? Thanks in advance.