My MATSHITADVD-R UJ-898 keeps ejecting my disks without playing. Why can I not play any of my dvd's or cd's?

So, I bought my MacBook Pro about 4 years ago. I had to take it in once to replace the screen. Everything worked fine until one day I could no longer use my optical driver. I have the MATSHITADVD-R UJ-898, but it also says I have Hitachi HTS545050B9A302. So, I need to know how I can get my driver to work. I know it has to be a software problem because I take good care of my Mac. And if it is the laptop, then I over paid for a very crappy computer. Please have some good news into what I can do!!!!! Thank you so much!!