Firstly, uninstall the graphics card driver if you are switching brand. Then turn off and unplug your PC before opening it up. Next, you can unplug any auxiliary power connection your existing card uses, and undo the rear expansion bracket screw(s) and set them aside. Your graphics card slot might have a retainer mechanism, so as you lift out the old card, you will have to reach under the card and press the latch down to unhook your old graphics card. If you have done all this, you can follow our guide.