If the dodgy disk is mounted internally check first what is shown in the BIOS.
If you listen closely and particularly if the HD is a temporary lash-up dangling (almost) by its leads, you should be able to hear some faint spinning sound.
If you have a suitable enclosure you could see if you can make a USB connection using that.
If there really is no sign of life whatsoever then IMO it has gone home.
I took look at the Seagate site. It isn't sparkling, but its downloads are presumably as up to date as you will find.
This is pretty fundamental stuff and only dates as new tech comes along.