Hi, here's the lowdown: Just built a new computer with -> M2N-MX SE Plus, X2 4200+ AM2, Knigston KVR DDR2 800 2GB(2X1), OCZ 610W PSU, X1950Pro, 250GB SATA HDD. The MB has Bios Rev. 0302 (latest).
 
The problem: At first I put everything in and fired up the computer, but no post, no beeps no nothing. The fans all spun up ok. So I went and cleared the Cmos, just to be sure (the MB was brand new), Still nothing.
 
Since it has onboard video, I proceeded to remove the GFX card, extra ram stick and sata cable. Booted up the machine, and was greeted by the Wrong Cmos message due to the Cmos clear i did just before.
 
Went into the bios and configured everything as it's supposed to be (mostly left the settings @ stock, but adjusted the time and the boot sequence). Rebooted.
 
Everything was fine at that point, so went ahead and put the gfx back in, hooked up the HDD and rebooted. Still going.
 
Then I went in and put the second stick of Ram in. Rebooted, NO POST..!!
 
So I took out both sticks, and reseated one, booted, NO problem. I took it out, put the other stick in, booted, NO PROBLEMS. I then put the second stcik in, tried to boot, but NO POST.!!
 
At that point I kinda tought that the memory may be defective, so I tried them in my main computer, booted up fine on the first try (this was done on a M2R32-MVP MB).  
 
Note that these sticks are rated to run @ 1.8V, and thats what the board is supposed to supply on default, but since there's no option to change/check the memory voltage, I can't be sure.
 
So I'm stuck there since I'm perfectly sure the Ram is good (both sticks), but there's 1 thing that's bugging me, there's an option in the Memory page of the BIOS regarding "Ganged and UnGanged" mode. I read up that this is for the AM2+ CPUs, and that if you set it to "Unganged" it kinda forces the memory to operate in single channel mode or vice versa, but the information I gatehred is pretty vague, and since this board is more low-end, there's not much infromation on the web for it.
 
Anyone has had this board, and/or a similar problem?
 
Thanks.

Anyone?!

Bump

Yes I am haviing the same problems, I have 15 on these damn motherboards.
Very odd.
Seems to affect different cpus differently
A 4200 with 2 gigs ram (2x1) wouldn't go (Kingmax)
Put in a 4400 and it went.
Put in a 5200 no go
 
Changed brand of ram, no go. (Apogee)
Ordered some more ram, (Transcend) have to wait and see.
 
Same as you,  left the 2nd ram slot free and all the pcs went.
 
 
Also tried a 5200 with 2x1 gigs
Swapped between various motherboards some went some didn't.
 
It seems some of the boards are fussier than others.
I had bad checksum error on 2 and reset to default
Haven't worked out what the fix is (1 x 2 gig stick perhaps?)
 
 

Yeah, got some info about early BIOSes being hard to get going on those boards, mine was 0108 i think, got the 0302 on there and got it to boot with 2x1GB.
 
I also just buit a new computer with with another M2N-SE plus, that one has the 0209 bios, tried to boot it with 2x1GB of Value Patriot 800, no go. Flashed to 0302, did not go either.
 
Put in KVR 800 2x1GB, and it went, but i re-flashed it with the 0302 BIOS aftewards and put the 2x1GB Patriot back in and got it going with those also. Pretty stupid if you ask me, but hey that's what you get for buying budget parts I guess...
 
Hope this helps

I have one of these boards.  I installed the OS using one stick of DDR2-800 and then updated the BIOS from a downloaded file.  I then had to shut the machine down, unplug it, pull out the CMOS battery, install the second stick of DDR2, replaced the battery, plugged it in, and booted up without any trouble.  Very frustrating to deal with....