There should be an option in almost every BIOS regardless of how sparse related to Boot priority/order. For your model, if you look under the "boot" tab => boot option priorities, you can set your hard drive to the first boot device by selecting "Boot Option #1" and pressing enter, then select your hard drive from the list. Try this first and let us know if the problem persists.
Main: i5-3570K, ASRock Z77 Pro4-M, MSI RX480 8G, 500GB Crucial BX100, 2 TB Samsung EcoGreen F4, 16GB 1600MHz G.Skill @1.25V, EVGA 550-G2, Silverstone PS07B
HTPC: A8-5600K, MSI FM2-A75IA-E53, 4TB Seagate SSHD, 8GB 1866MHz G.Skill, Crosley D-25 Case Mod