I have a five year old Sony S2 which won't boot any more. I suspect it's the hard drive; I had to have it replaced two years ago by Sony for their flat $150 fee. Any thoughts on how to diagnose this? I can probably handle replacing the HD myself, but would hate to go through that only to find out it was the mother board or something else. Fortunately I have an S3 as my primary box. Thanks for the help!