I appreciate the effort you made to take on the challenge of repairing your personal hardware. However, in this case I'm going to have to disagree with the testing method that you used.
You claimed that your graphics card no longer worked because you were supposedly getting wrong readings on a couple of controllers/MOSFETs using a multimeter. To me it sounds like all you did was probe the devices without isolating them from the rest of the graphics card first. The parameters listed on datasheets often do not take into consideration external resistances/capacitances/inductances/grounds that definitely exist on or across the terminals of the devices that you were probing. What I'm saying is that in order to properly test these devices for failure, you must first remove them from the graphics card. This is challenging, and I do not recommend doing it before checking for more obvious signs of failure such as cracks or burn marks on SMDs and solder joints.