|Look for the drive in Windows Disk Management. If the drive is listed there, highlight it and post all that is reported.|
External USB drives consist of two components. The first is the enclosure itself. A working enclosure will show up in Device manage even if the hard drive inside is not functional. So, check Device manager to see if you have a mass storage device listed there. If not, you may want to remove the hard drive and connect it by other means.
Post back with your findings.