Nvidia geforce fx 5500 wont work?

Hi! i borrowed an graphics card of an old m8 of mine and its not working its the nvidia geforce fx5500 agp 256mb basicly i pluged it into the motherbored but id did see a 2 prong connector thing but nothing fitted it so i didnt bother with it my onbored graphixs av given up the ghost so if any 1 cld point me in the right direction ty