External hard drive not suddenly not working on MBP

Last year I bought a WD My Passport for Mac, and it's been working fine ever since I got it. However, today my MBP (Mountian Lion 10.8.5) did not recognize it. It does not show up in the system profiler nor in disk utility. I did notice in disk utility that there was a decryptedfile.dmg mounted, but I'm not sure if it's related to the problem. I tried connecting it to another Macbook, but it still shows the same problem. The light on the Passport is on, though it doesn't blink like it usually does. Someone halp!