I have an E machines desktop at home and sometimes when booting it will say OPERATING SYSTEM NOT FOUND. Usually if you restart it, Windows XP will kick in and run fine. My question is whether or not this is a start of the HD failing. I have a sony vaio laptop that started doing the same thing and eventually the HD went out completely. I have the computer under warranty, but usually they send someone out to look at the specific problem. The problem there is that he will want to see the specific problem and a lot of times the computer starts up fine. Does this sound like a HD problem or what else could be causing this?