I cant play dvd's!!?

For some reason, my dvds arnt working. It was working over the apst years i had this computer but all of a sudden it stops working.When i right click my dvd/cd drive and go to properties, theres a pie chart that blue and theeres no pink. Please i dont know whats wrong. The first time i found out about this was when i burned some anime into a dvd+ cd and it wouldnt play on my comp after i burned it. i thought if i left it alone for a few days it would work but it didnt, than a couple of months-.-...i tried downloading a dvd decoder and that still doest help. please help me!!!