The driver thats not installed is called ATK0110 ACPI UTILITY and you will find it under System devices in the Device Manager once the driver is installed, all you have to do to install the driver is insert the Asus Support CD and it should get installed automatically, or you can install either Asus PC Probe II or Asus AI Booster, doing any one of the three should install the missing driver for the unknown device.
Hope this helps!