External Hard Drive help

Quick problem- My external hard drive stopped working with my laptop. It's a no-name brand that I bought off ebay, and it was worked fine up to this point. It's USB powered, and my laptop is a dell inspiron 600. Anyway, each time I plugged the drive in, the laptop would assign it a new drive letter (I:, J:, K:, etc.), and I think that it would reset each time I turned off my laptop. Anyway, it got to Z: last time and when I plugged it back in, the Hard drive would power up and the computer would make the "device connected" ping, but there would be no icon for the hard drive. It's still listed under the devices in the computer manager, and it says that it's connected, but I can't find a way to access it. However, if I take it to my desktop, it connects fine- so it's not a problem with the hard drive itself, just its connection with my laptop. I'm not sure if it has anything to do with the fact that I plugged it in after it had gotten to letter Z:, or if that's just a coincidence. Not a huge problem, but I use my laptop much more than my desktop, so it's quite a pain that it's not working. Thanks in advance for your help!