As u mentioned, the motherboard was bad. I got a replacement with Mega 865. This system is working ok except for one problem.
If I turn on the PC with a CD or DVD in the drive, I am able to explore the CD/DVD and able to watch movie or install application. If I replace the CD/DVD, windows is not able to read it anymore. Windows explorer hangs if I click on CD drive. It starts working again after I restart. Its like every time I chnage the CD/DVD, I need to restart the PC !!!
I have a BenQ DVD writer in the system. MSI recomends to use their own MSI optical drive for mechanical compatibility. With BenQ drive I dont see any other issues except changing disks.