The key is to check the HD manufacturer's website on how to enable the SATA 3.0 HD to run on a SATA 1.5 motherboard/controller. Some will work automatically. Some will need to have a jumper set on the HD (or other fix).

Here is an example from Seagate:
http://www.seagate.com/support/kb/disc/faq/sata_lock.html