I just am stmped , this computor was working great , i left it on while away to the store and it was shut off , didnt think anything about it , untill i turned it on , all it dos is turn on spin the fans and about 4 sec later shuts off , it about 1 half yrs old , nothing else was put on it or downloaded to it , no storms or surges , i checked the fans , all are good when it turns on , so what can i look for and test when i open it up and look at what might be an issue , its win vista and had not any thing gone wrong untill now so it turns on fans spin and the shut off ????????????? thanks , where should i start