Help me with my external HDD, please?

Hi,

I own a WD 1TB My Passport HDD. It supports USB 2.0 + 3.0. I bought it a little over a year ago, and it's still under warranty.

Now, the problem is that whenever I plug the HDD into my PC, the light comes on. It's detected by my PC. The drivers are successfully installed. But, the partition itself never shows up in My Computer.

I don't know why this has happened. The HDD did have just 2/935 GB free but that can't be the reason, right?

For security's sake, I tried plugging it into different ports on my laptop. I even gave it to a friend to try out on his laptop. No success :(

Help? It'd be highly appreciated :)