Problem:

The combination of the ASUS M2N-MX SE PLUS Motherboard and two OCZ PC2 8500 (5-5-5 @ 2.1-v) 1GB memory modules caused an unbootable computer that was unable to POST. Using only one memory module in either memory slot on the motherboard would allow the computer to boot. We have a solution that worked for us, hopefully it will work for you too.

Solution:

  1. Shut off the computer and unplug the power cord. Install the second memory module. Remember to always touch part of the case before touching the motherboard or any other electronic parts inside the computer – this reduces your risk of causing damage due to static electricity discharge. Ideally you would be using an anti-static wrist strap.
  2. On page 1-21 of the ASUS motherboard user guide you will find instructions to clear the RTC RAM. This essentially clears the CMOS. If you don’t have your user guide handy, the instructions can be found here: asus_m2n-mx-se-plus-manual-p21
  3. After performing the “Clear RTC RAM” steps, plug the computer back in to power and turn it on.
  4. When your computer starts, you might hear a beap, and you should be instructed to press F1 to configure the BIOS. Go ahead and press F1 at that point.
  5. Once you have entered the BIOS setup, go to Advanced->Northbridge Configuration->Memory Configuration, and set Unganged Mode Support to Auto.
  6. Press F10 to save the changes and exit. At this point the computer should boot normally with both memory modules installed.