Noob is right. Those MR style bulbs burn out all the time. I cant tell you how many service calls I have went to just to replace those in retail stores. They are popular with clothing stores for some reason. As for your question, what were those sockets used for previously? They look like they plug into a track light? Those bulbs will be low voltage so you need to make sure that those sockets either have ballasts or the Track has a ballast to run them.