That older HD with the HDD Password set? I put it back into the gateway P-7811 FX laptop after the bios had been flashed back to what it was when the drive worked - it asked for a password but nothing worked. Nada. So I put the new drive back in and it worked fine. Still had an unusable 200gb drive. It wouldn't even work with an external USB adapter - not seen as a drive.
I took the drive to work, put it into another laptop and it came up asking for the password, which it then accepted and I was able to get into bios, remove the hdd password, and was able to then connect the drive to an external USB adapter and browse the files on it. I don't need them anymore, so I am now happily formatting it so I can use the drive later as needed.
So the learning experience is to never flash a laptop bios with a HDD password set. And to recover the drive, you may have to use another laptop to reset the HDD password.
In other news, my laptop is working fine, I backed it up last night just in case I do anything else silly.