Password on a SATA hard disk

I would first like to thank all those who give some of their time to render service to others. I hope I'm in the right section and all my apologies if this is not the case. I have a little concern with my pc despite all the research I made on the net
try to solve but unfortunately I am not alone failed. I have a PC with a Dell flat unit with an Intel Celeron 2.8 GHz, and a 80 GB hard drive Western Digital SATA. I put a BIOS password and on my hard drive and password was the same for both. Unfortunately, my grilled food and I've changed a few weeks after. To my surprise, my password most recognized neither by my bios, or my hard drive.
For the bios, I remove the battery and change the jumper, for against my hard drive, I have failed to find a solution from the change.

I thank you in advance for your help and advice

I see very well procedure have you done to remove the password to your BIOS - that it was saved in the memory ROM and your motherboard is the change of food that you have raised this problem detection Start-up: you change the power supply, motherboard and processor is like if you went on a new Windows PC and it will re-detect all your components restarts ..

For the password to the hard disk I do not pass it or go home.
Is this just after the start of the BIOS?
During the change of Windows (I doubt it anyway) or you simply speak the password for your Windows session.

Thank you for your speech, I spoke password on my hard drive parameter that I returned to my bios before the sake of food.
the pc wonder just startup when the screen is black even before the launch of the operating system.