|Are you sure you downloaded the correct BIOS? Often there are multiple versions of a MB and they each require different BIOS' for example, if the board comes in a version 1,2, & 3 and you have Version 1 but install a Version 3 BIOS which may have different internal components, some of them might not operate properly.|
Try BIOS set up as recommended above first.
If you have to downgrade a BIOS, you download and install it just like you would an upgrade install. If the automatic or Windows BIOS utility fails on this, there may be a Flash Drive BIOS Flash utility that probably have more ability to install the downgrade BIOS.
As mentioned, ONLY update a BIOS if there is a significant reason for it such as either there is a problem you are experiencing and the update specifically says that is addresses your particular issue, or you are upgrading to hardware (CPU, Video Card, PCIe SSD drive, etc.) that only the new BIOS supports. THEN by all means proceed but with extreme caution after understanding all that can go wrong and all you can do to protect yourself from them (I strongly recommend using a UPS while doing it).
You have to be a little bit crazy to keep you from going insane.