denford, this is usually caused by a bad hard drive. first check to see if you can access the BIOS. Check to see if your hard drive shows up in the BIOS. then check your boot order, make sure that you have the hard drive selected as first boot device. If the HDD does not show, your drive most likely has failed. You can try and set the boot order to either boot from optical drive or USB and use a recovery disk or Live Linux disk and see if your computer starts up. I am not sure how you determined that the HDD is "working good"