My external hard drive wont show up anymore in "My Computer". Help!?

I have a 1tb Western Digital external HD. It always used to come up under "My Computer" as "My Book", the E: drive. I just went to go open it up and it was no longer there. I looked at the HD itself and it looks like my girlfriend unplugged the power adapter from it. I plugged it back in, the lights came on, and in the bottom right corner of my monitor said it was looking for the drivers. Few minutes later that went away so I tried My Computer again and still wasn't there. Hit refresh, nothing. Restarted my computer, nothing. I unplugged it from the USB port and plugged it back in, still nothing. Am I missing something very blatant, or am I screwed?