2 beep error code K9N SLI Platinum

System is as follows:
Seagate 500GB SATA HD
1 XFX GeForce 8400 GS
Samsung 18x DVD RW
AMD Athlon X2 5400
Corsair 2048 PC6400 DDR2 800Mhz

I have replace the power supply, the memory and the MB, and I still get a 2 beep error upon boot. I checked MSI's website, and this code is suppose to be due to parity circuit error. The system seems to be stable except for the H/W Monitor menu within the CMOS. I can enter in to the H/W menu but within about 30 - 60 seconds it locks up. This is the only part of the cmos that I experience any problem.