Reinstall drivers for the SABERTOOTH X79 board SATA Marvell_V1201014_XPVistaWin7. Then don’t just reboot, turn off the PC and reboot.

I believe that control is hot swappable and in the process of copying something to the drive, then running sysinternals SYNC at same time, forced the drive to disconnect possible in hot swap mode, not sure. Made drivers go funny. Installing drivers and rebooting made no difference. Turning machine actually off then on again, kicked the drive back to life. I think because restart is just a soft restart is reason it never came back up then.