What is a 3 prong grounding plug? Is it the power wire a computer comes with?
After you unplug the computer, make sure to push the power button and you will notice the power light will flash a second. That releases any saved or buillt up energy in the computer. Installing a card is not hard you will see, do not use a magnetic tip screwdriver though, alls you should need is a phillips and then just pull the slot cover out and install the new card, make sure that it is pushed in all the way and put the screw back in.