Windows 7 notices but does not 'see' external usb hard drive

Plug in the external USB hard drive.

Right mouse click on My Computer 

Left click on Manage 

Double click on Storage

Double click on Disk Management 

Disk 0 is Hard Drive Partitions.

Disk 1 will display the SIZE of the external device with no name

Right mouse click the blue colored bar              on Disk 1 

Left click on Mark Partition as Active 

Left click on Change Drive Letter and Paths

Right click the “Add” button  - Right click OK 

Following is the end result. The external USB device should now have a drive letter.