Upon startup, Harddisk error "Hard disk1 3F1" but can start up using F9

Hello Everyone-

Hoping for some guidance on my son's laptop issue (Pavilion dv6 - LW260UA#ABA). Obviously a dated unit, purchased for when he first went to college, but still worked great, up until recently.

The original problem was the fan burnt out, and thus the laptop would not start. I purchased a new fan and installed myself, was fairly easy. Upon starting up the computer, I got the "Harddisk error "Hard Disk1 3F1" error. I ran all of the appropriate tests, and everything, including the Hard Disk Test, came up fine. No errors. I re-booted, and the "Hard Disk1 3F1" error came up again. Re-ran tests, all clear, no errors.

At this point, I thought maybe I hadn't put the unit back together correctly following my installing the fan. I took another Pavilion dv6, same exact model with no issues, put this Hard Drive into it, and still get the same message. So at this point, I'm thinking the Hard Drive must be bad after all.

Before I gave up, I did find a video online showing how to boot up in a situation like this. When rebooting the computer, I hit ESC, got to the startup menu, selected F9 Boot Device Options, selected Notebook Hard Drive, and voila, it starts up into Windows just fine. Computer works great, not slow, everything functions as normal. BUT when I restart it comes up with the same "Hard Disk1 3F1" error and I have to go through the F9 process to get Windows up.

So do I truly have a bad drive (considering it's in a different case than the original one)? Being that the issue happened after the fan burnt out, did the unit overheat causing damage to the drive or other components? If the drive truly is bad, are aftermarket replacements available, and if so is it easy to figure out what the correct replacement drive will be?

Thank you everyone in advance for your time on reading through this.