Computerhilfen.com: matshita dvd ram uj811

hey guys, ive been having problems with a second hand computer (http://www.computerhilfen.com/explanation-c-Computer.html) ive just bought, shes old, its a averatec centrio, the dvd (http://www.computerhilfen.com/explanation-d-DVD.html) device is a matshita dvd (http://www.computerhilfen.com/explanation-d-DVD.html) ram (http://www.computerhilfen.com/explanation-r-RAM.html) uj811m when i turn her on some times the dvd (http://www.computerhilfen.com/explanation-d-DVD.html) graphic there,some times not!!but she would still open when i push the  button but now its doesnt show or work at all!!!! its sad, but i dont want to throw her out the window but its getting close!! help!!! >: