I am having this problem most of the time from a long time. When I turn on my PC it turns on for a while maybe around 5-6 secs then it turns off automatically and it keeps on repeating untill I dont switch of the main power. During the repeatation cycle when I tilt my computer sideways or all the way horizontally then only it will turn on as normal. I am really fed up with this problem and a solution would be greatly appreciated.