The first thing you should do is to connect the drive directly to a system via its native interface (Parallel ATA in this case) connection. In other words do NOT use a USB adapter. If the drive is recognized by the system (BIOS Setup), then you can boot Windows and see if the drive is recognized by Windows as being formatted (good) or unformatted (bad). If the latter then most likely the file system has been damaged but the drive may still be readable, and therefore files may be recoverable.
If the drive is not recognized by the system at all, then the problem is more serious and you will most likely want to send it to a professional. You can try swapping the logic board from an *identical* make and model drive, but if that doesn't work then swap the original logic board back before you send it out. For a professional service I recommend Seagate In-Lab Data Recovery
. Let me know what you find, Scott.