problem with my 2007 macbook

ok ive got a 2007 macbook and all of a sudden today the screen just froze and then it got all light until it was completely white. so i restarted it and then it was fine but it did it again tonight and restarting it didnt fix it so i waited a lil bit with a white screen and then it popped back up not frozen and was fine. please help! i love this computer i really cant afford to lose it right now.