Below is a copy/paste of what someone else posted, an e-mail from ASUS tech support.
If you! r system doesn't send a signal to the monitor when it's powered on, there are several potential causes. Your problem could lie within the motherboard itself, or with a component installed on the board. It could even be caused by grounding or EMI. Please follow these steps to troubleshoot:
Before going through these steps, please verify that you have everything installed properly. Reference the user's manual for any specific memory configurations that must be used, as well as additional power connections. New AMD and ALL Pentium boards, have TWO POWER CONNECTIONS that MUST be made. 20pin, and 4pin 12v connections. Not connecting these in the proper location will cause the system to not post. If you have verified this, then please continue with this troubleshooting procedure...
First you want to do is pull the motherboard out of the case. Place onto piece of cardboard or static mat. Limit the system down to the bare components. Videocard, memory, processo! r, and external speaker should be the only things that you have attach ed to the system. Clr the cmos battery, make sure that you unplug the power from the board, take the battery out, and then short the clrtc leads for 10-15 sec. After doing that power the system back on. If you still don't get anything, then you want to try and force a beep code. Power off the system, remove the videocard, power back on and listen for beeps. If you get beeps then you need to test that device to make sure that it's not defective. If no beeps, then go on to remove the memory, power back on and listen for beeps. Then the last thing to do if you still do not get beeps, is remove the processor and power on without the cpu installed. If nothing ever gives a beep code, just check to make sure that your speaker works, and is plugged in correctly, to the lime green line out port onboard. If you still experience problems at that point, then I would either return the board to the place of purchase, or you can send it in to us. To send in for warranty repair, please cont! act Customer Service at 510-739-3777 option 3. Thank you!
BASICS
Start by making sure all connections are made properly, and that the power supply is plugged in and turned on. Check your heat sink and fan to make sure they are installed in the correct position. Make sure that all of your components (processor, video card, etc.) are compatible with the motherboard.
GROUNDING/EMI TROUBLESHOOTING
Check that the MB is not picking up EMI (Electromagnetic Interference), or improperly grounding against the case. Please remove the MB from the case and set it up DIRECTLY on the cardboard box it came in or some other non-static, non-conductive surface, like a telephone book. Install the power supply, processor (with heat sink and fan), memory and video card. If the motherboard has the vocal POST feature activated, plug speakers into the onboard audio jacks. If the board doesn't have this feature, or if it's been deactivated, make sure to install a ca! se speaker on the board.
If the system now POSTs then your prob lem is caused by grounding. You will need to electrically isolate the MB from the case to correct it. To do this, you will need to use electrical tape to cover the brass standoffs that support the MB, and insert paper washers between the MB and the heads of the mounting screws. The red paper washers should be included with your case hardware, or they can be purchased at Radio Shack or a computer store.
Make sure that no standoffs are placed in a spot where the motherboard isn't designed to be grounded, as some cases will have different standoff locations to accommodate different styles of motherboards. Also check that there are no other metal objects that could contact the motherboard or any other electrical device attached to the system, such as a metal burr, loose screw, metal rod, or any other object that could cause a short.
POST CODE TROUBLESHOOTING
If the system still won't POST then determine which, if any, error code is being generated. Mothe! rboards with the vocal POST feature will "tell" you what is wrong, i.e. "System Failed VGA TEST" or "System Failed CPU Test." Beep codes and their meanings can be found in your User's Manual. Investigate any error messages (System Failed VGA Test, or one long and three short beeps, indicates a possible bad video card, etc.) you receive in this fashion.
If the system gives no POST error codes while refusing to boot, follow these steps:
Remove the memory entirely and boot the system to try to force a POST error. The beep code for no memory is 1 long continuous beep, or several long beeps in an endless loop (or you may hear "System Failed Memory Test" in a repeating loop). If you do get an error, try a different stick of memory to see if that fixes the problem. If it does, the original stick of memory may be bad. If it doesn't, you may have a problem with your MB. Proceed to the Power Supply Troubleshooting procedures.
If you don't get any POST erro! rs, remove the CPU from the board and boot it again. If you have a MB with the vocal POST feature, you should hear "No CPU Installed" or "No CPU Found" repeating error messages. If you hear these messages, it's very likely that you have a bad processor. If you don't hear these messages, you may have a problem with your MB. Proceed to the Power Supply Troubleshooting procedures.
Next, test the CPU. You want to test the CPU in a known good, working MB. If you test on a motherboard that you know works and the CPU still does not work, you know you have a bad CPU. If it works correctly on the second motherboard, you know that your CPU is not the problem.
POWER SUPPLY TROUBLESHOOTING
Please check to make sure your power supply can provide enough power for your system. We recommend using power supplies that can provide these output levels:
300-Watt Power Supply
+5 Volts @ 28-32 Amps, +12 Volts @ 10-13 Amps, +3.3 Volts @ 24-28 Amps
350-Watt Power Supply
+5 Volts @ 32-38 Amps, +12 Volts @ 12-15 Amps, +3! .3 Volts @ 26-30 Amps
400-Watt Power Supply
+5 Volts @ 35-40 Amps, +12 Volts @ 14-18 Amps, +3.3 Volts @ 30-34 Amps
450-Watt Power Supply
+5 Volts @ 35-40 Amps, +12 Volts @ 18-22 Amps, +3.3 Volts @ 35-39 Amps
500-Watt Power Supply
+5 Volts @ 35-42 Amps, +12 Volts @ 20-24 Amps, +3.3 Volts @ 38-42 Amps
The specific power requirements for your system will depend on many factors, chief among them being which processor and video card are installed. Newer processors with faster fsb will require more power, as will newer video cards with faster and more sophisticated GPUs. Using a more potent audio card (or using the SoundStorm or SoundMax onboard audio systems on our motherboards) or a second video card will require extra power. Installing extra case fans (more than one or two) will increase power usage, as will SCSI or ATA controller cards with extra drives installed on them. Make sure you've selected a supply with sufficient output. If y! ou're not sure how much power you will need, please contact Technical Support at the telephone number below for assistance.
At this point your system should be stripped of most of its components. Try installing a different power supply of equal or greater power to see if the system boots. If your original power supply is underpowered then one with greater wattage should start your system. If your system still won't POST, your problem is most likely caused by the motherboard.
If you determine the motherboard to be the cause of the problem, you can contact our RMA department to have it repaired or replaced. Please be ready with your case number and the board?s serial number, then call 510-739-3777 option 3.