Try checking your BIOS voltage settings for the memory. I have the same MB & had nightmares trying to get it up & running until I discovered that the auto settings topped out at 1.91V (I think) and my OCZ memory needed 2.21V. Changing it from auto to manual & adjusting the settings worked wonders for it.
Thanks DGKing. I think that is the problem with mine also. It did not work at 2.0v for DDR2 which I already tried. I did not feel very comfortable jacking up the memory voltage further because it worked fine in other machines. After reading your post, I increased the memory voltage to 2.25v and now the replacement board does boot fine (with an idle power consumption of about 37W). But my original board still does not work, it still keeps re-starting. But it worked the first time I tried after increasing the voltage!
I am sure I can get at least one of these boards work with increased DDR2 voltage. This has been my worst experience while assembling a computer in 10 years.
Core/Hybrid: Foxconn N570SM2AA-8EKRS2H (has 2 network ports), ASUS EN6200LE, AMD-X2 4000+, 1GB DDR2-800, 500 GB SATA/300, DVD drive/writer, Sony XL1B3, BTC 9019URF, Gyro Mouse, Gyro Remote, USB-UIRT, MS Win XP Remote, ATI HDTV Wonder, HDHomeRun