The drive may be trying to take more power than the USB port can supply. The port should offer 500 mA to a USB device, but sometimes on notebooks, especially, it can't.
If the drive works, you could simply disable all USB port warnings. You can do this in a couple of places: control panel, system, hardware, device manager, USB universal host controller, right click for properties, click on advanced, tick the box that says "Don't tell me about USB errors"
You could also suppress the message by customising the task bar.
If the drive doesn't work, then you are indeed taking more power than the port can supply. One way around this is a double-headed USB hard drive cable which uses two USB ports to get enough power. These used to be common with older drives. Another way would be to use a powered hub. There's also a slim chance it's a bad USB cable.