New Internal harddrive

I bought a 2tb internal 3.5 harddrive, and put it in a sleeve to make it my external...at the time I was running Vista 64b, and now im running win7 64b. Same as before with vista, when I plug it in, the computer instals the device driver, and then says ready to use. When I open My computer, as to access the drive, it is not visible. I tried this several times, after a fresh reformat of the computer, I tried veiwing the device under the eject device icon thiny on the start menu bar, and nothing. When I bought it I asked the guy where i bought them, is this compatable with this and that, and if it will support 2.0 usb not 3.0. I was good to go. Well, no im not. Reason im asking on here is cause i cant return it now cause im not in the states and its out of date anyway.