reseating the drive means removing the drive, and securely placing it back in. Particularly with mobile devices, things get jostled and connections get loose.
If you are sure your connection is good and BIOS still does not see the drive, then you have a hard drive failure. To ensure it is not the device, remove it, and try using it as an external device on another computer. You will need to obtain an adapter.
If it works, then you know it is your connection.
and btw it is LT. Tedster and I am a he. haha