Yeah try opening the ASUS splendid utility and changing it back to normal. Let me know if that wasn't the issue but usually it's just accidentally hitting the function combo shortcut for that
G75VW-BBK5 Windows 8 Pro 1TB HDD, 180GB Corsair Force GT Sata3 SSD, 16GB DDR3, GeForce GTX 660M, Intel i-7 3610-QM 2.3Ghz Turboboost to 3.3Ghz