I have an 17" aopen

Hello
You've said that there is no start up with your hdd even you hdd is defective your CPU will turn on and have display in your monitor try to turn your computer on then push the button delete or a f1 button it depends on your bios that you have using. If your PC tun and display the bios it means your motherboard is good. Then in the bios set up put it in the main section you will see if your HDD is detected by your PC if not then you HDD is defective o have a lose contact on its connectors.
If you don't have a display try to check if your CPU have a video card. Turn off your PC then pull out VGA connector that are connected to your computer then pull out the Video card in your motherboard which connected to a PCI slot then tun on your pc using the on board VGA connector which is located at the back of your CPU which is beside the parallel port and on the lower of the mouse and key board connectors. If the problem is still there try to clean your Memory cards which is located inside your CPU unit and located at the left side your motherboard and beside your processor. Clean it with a pencil eraser. Then put it again in your motherboard. If problem is still there. Try to check your power supply may it dropping voltage where the did not full fill the requirements of your computer. Hope this will help.