Hi, I have a hp windows vista laptop. For some reason when I click the power button it starts to turn on(buttons lights up) but theres no visual on the screen, then it just turns off by itself (lights on buttons turnsoff then turns on again automatically repeatedly) it keeps doin this: on and off on and off, until I hold down the power button to completely shut it off. Why is it not turning on right? And how can I fix it? I have all my stuff in that laptop and don't have a backup disc!! Please help, thanks!