HDD Missing

My main PC is a HP, maybe 2008ish? It's on Win 10 with 3 internal SATA HDDs:

Seagate ST3500630AS (Boot)
Seagate ST31000340AS (Disk 1)
Samsung HD103UJ (Disk 2)


Disk 1 has gone missing, it's no longer visible in This PC or Storage Manager, but shows up in BIOS (hence model numbers above).

I've tried swapping SATA sockets on Disk 1 & 2 but no change.

If it's visible to BIOS then surely Windows should see it too, maybe with a corrupt or missing volume?

What can I do to diagnose/recover? I don't have an external USB enclosure to test the drive off another PC, should I get one?

SeaTools (run from Windows) has found Boot and Disk 2

Does Windows Disk Manager see it?

(Start/Run COMPMGMT.MSC, Storage, Disk Management)

Does windows Device Manager see it?

(Start/Run DEVMGMT.MSC, Disk Drives)

If neither see it, then I believe this indicates a hardware problem with the disk, the cable, or the SATA socket/controller.

There can also be some BIOS settings that might make the disk disappear, and certain kinds of hardware issues can cause the BIOS to change settings too.

Doesn't appear in Disk Manager or Device Manager. My first thought was BIOS but no settings in there. I'll try a different cable, already tried a different socket.

I thought if the disk had failed completely then it wouldn't appear in BIOS either.

Definitely the HDD, just stuck a replacement in and it worked straight away on the same port/cable. Just need to see if I can recover any data off the old one now, just my last few months podcast downloads.