Do you have a direct to bios button on the motherboard it`s self ?
With some Asus boards there is a button on the board you press.
If you have just built the system.
You must first connect the monitor video lead to the on board video output ports of the motherboard.
To get a bios display image on your monitor.
When pressing the key to enter your bios settings.
Via either the VGA port provided, or the Dvi video port on the motherboard.
i dont have a graphics card
If you connected the monitor video lead to a Pci-e based graphics card in the pci-e Slot of the motherboard first of all, remove it and use the motherboards video output ports.
You should then see the bios screen and options.
Change the default primary graphics card to initialize first to Pci-e, or Peg interface mode.
Save the new settings in the bios before you exit it.
Then swap the video cable from the motherboard video output ports to the Pci-e based graphics card video output ports.
From then on the bios screen will be displayed via the Pci-e based graphics card in the system, when the key is pressed to enter the bios settings.
It catches a few people out if it`s there first system build, as to why the bios screen does not display, when the key to enter it is pressed on the keyboard.