Ok. Power down the system. Disconnect all power sources (monitor, power cable, powered speakers, etc). Press the power button to discharge any residual power (not kidding). Install the adapter. Connect the adapter to the HDD. Be sure to connect the power cable to the HDD as well. Reconnect the items removed earlier. Power up the system. Wait for Win 7 to load the drivers. Partition/format your HDD and you'll be done.
You don't need to do anything in your BIOS.