Hello i think you need the usb driver from here:

http://www.ecs.com.tw/ECSWebSite/Product/Product_Detail.aspx?CategoryID=1&DetailID=436&MenuID=24&LanID=0

If any other drivers missing install them.
Look in the device manager for drivers problems.

Seagate has the support for your product:

http://www.seagate.com/support/external-hard-drives/desktop-hard-drives/onetouch/

You maybe need some software for the drive:

https://apps1.seagate.com/downloads/request.html

Enter the model or serial number to find any software.

Good luck