USB 3.0 NOT WORKING

Hey guys!
I'd just recently built my pc and it was all fine until I realised my USB 3.0 is not working.
Whenever I insert an external HDD, the led on the hdd flashes, then turns off.
However on my BIOS, it recognizes the HDD.

I've got a GIGABYTE GA-Z77X-UD3h-WB WIFI and currently using Windows 7 64bit.

I've downloaded both of the USB drivers off http://www.gigabyte.com/products/product-page.aspx?pid=....
Should i have done that?

Thanks guys!