External hard drive doesn't show up in My Computer

Hi, so I have a 1TB Seagate External Hard Drive, and I've been trying my damnedest to get it to show up tonight. It's worked fine for years -- even a month or so ago! -- and on the computer I'm using as well, but for whatever reason, it suddenly doesn't want to show up in My Computer. I haven't dropped it or anything.
Whenever I plug it in or remove it, my computer makes the recognition noise, so it acknowledges that the device is there. I tried uninstalling and reinstalling it, but that didn't work, and, of course, I restarted my system and it still isn't working.

I've tried running Disk Management, but whenever it prompts me to initialize it, I get an error message when I try both the GPT partition style ("The specified disk is not convertible because the size is less than the minimum size required for GPT disks.") and the MBR partition style ("The request failed due to a fatal device hardware error."). I've also tried pulling it up through Diskpart, but it doesn't acknowledge the disk is present. Unfortunately I don't have any other well-functioning computers in the house that I can use to check to see if this occurs elsewhere.

My system is Windows 8.1 on Intel Core i5-4210U CPU, 64-bit OS and processor, and 4GB of RAM. If needed I can provide any other information.