I have shut down my computer two hours ago. When I open my computer it started restarting itself after showing the POST screen. I can open my computer with a Ubuntu Live CD or Windows installation CD. I can also open and boot my computer with my second drive, so I think something is wrong with my primary hard drive. Do you have any idea what the problem might be and how can I fix it? I am using an HP DV9087EA laptop and my primary disk is a WD500GB. I have installed Ubuntu 10.10 and Windows 7 on my drive.