I am looking at this one for a friend. It is a Dell Inspiron 2500 running WinXP Pro. POST is OK, but it gives an "Operating System not found" error after POST on some occasions, boots normally on others. The OS also gets unstable at times. I was told that it would sometimes randomly open old text files without being told to, and then lock up. With the error message, I am thinking maybe the HD is going, but I don't have another to test it with. What do y'all think?