I gave my laptop to service center for keyboard problem. They replaced it with new and returned to me. It was worked well before shutdown. Then when I restarted, it is not booting. And it is not entering to Bios also. Without hard disk, it is entering in to bios. then I checked the hard disk with another laptop. it is booting well. Then I used another laptop's hard disk in my laptop. it is booting well. But my hard disk not booting with my laptop. Pls help to come out of this.