Well, let's start with the simple stuff. Is it plugged in? Next, is it plugged in correctly?
The case has the new USB 3.0 header, and your motherboard only has USB 2.0 headers. Did you plug the case USB 3.0 cable to the included adapter, and then plug that adapter into one of your motherboard's USB 2.0 headers?
USB3.0 cable->USB3.0-to-USB2.0 adapter->USB2.0 motherboard header
If you have it correctly connected, have you made sure the motherboard headers are not disabled in the BIOS?