Hi,
Most bioses have a system voltage monitor, check this, 64bit does make the CPU run harder and a bad power supply can cause the problems you are seeing.

Also check that it is the correct ram for this motherboard.

Also check the video card drivers are up todate.

>>What does the event viewer show? I would check that first. Also, have you researched the troubleshooting steps and known issues?
>>http://technet.microsoft.com/en-us/library/dd367847%28WS.10%29.aspx
>>http://technet.microsoft.com/en-us/library/dd349347%28WS.10%29.aspx
>
>Well, I think we can put that on the memory. I am running the test since 30 minutes and am at 47%. The number of errors is at 35850.