Does it show up in Windows disk management? Can you assign it a drive letter? Can you reformat it, since there is no data on it yet?
Also, you should check to see that you do not have the USB read only protection of Windows enabled, it is a single registry key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\StorageDevicePolicies The value 0 = not protected, 1 = read only.