See the WD SES Device USB Device Driver list below. If you have an external Western Digital SES drive then this is the USB driver for the device. Most operating systems will use a generic driver for the portable hard drive however this is the WD USB driver for the device. It is a very small file and installs like any other piece of software.
WD SES Device USB Device Driver
Note that this was the latest driver released from WD for the external drive. Download the ZIP file below and extract or open the file. Inside you will find the install file in an EXE format. Double click on the file and the program will install in less than a minute. Below are both the 32bit and also the 64bit versions of the software.