Check the Hardware section of the user manual. If it's blinking ON for half a second, and then OFF for half a second, then you've either got a cable or driver problem. To quote from the user manual:
When the blue LED blinks on for half a second and off for half a second, this indicates that the hardware is being powered by the computer but there is no valid connection between them. This could indicate the USB driver is not installed correctly or because there is a problem with your USB cable. For more information on how to properly install the drivers please go to the Installation section and the Troubleshooting section.
As per the manual, check the Installation and Troubleshooting sections. Are you using the supplied USB cable?