The Game Desktop within Rotation Desktop depends on Game Fast, Power4Gear, and Splendid, as well as some other controls. Have you uninstalled any of the ASUS applications on your system?
If so, an ASUS Factory Restore (F9 at the ASUS splash screen) will probably restore Game Desktop functionality, but it will overwrite your OS partition if you choose Option 1 or your entire entire OS disk if you choose the other options.
It is also possible something installed to your system is conflicting with GameDesktop.exe. What Antivirus, AntiMalware, Firewall, or Remote Desktop software have you installed?
G74SX-A1 - stock hardware - BIOS 202 - 2nd Monitor VISIO VF551XVT