Cannot Change Boot Priority Among Hard Drives?

Originally I had a small solid-state hard drive on this set up. I added a non-solid-state hard drive later. Recently, my solid-state drive, the C Dr., became too full to upgrade certain software programs such as Dragon NaturallySpeaking. I purchased a second solid-state hard drive.I "mirrored" that second solid-state hard drive. To make sure that Windows was operating appropriately, I rebooted and hit F10. I then showed the new solid-state hard drive. Everything booted perfectly and the new solid-state hard drive was noted as the C Dr.When I rebooted into bios to change the hard drive boot order so that the new second solid-state hard drive would be the first in the priority, when I highlighted it and exited from it,it still showed the original solid-state hard drive as the first hard drive.I have never had this problem before. I now have to go into F10 every time I boot into my computer and highlight the new solid-state hard drive.