Dell PowerEdge 2650

Clarifications

Turn off, remove the RAM and clean the contact edges with a soft rubber/eraser and then refit and test.

9 times out of 10 this should cure the problem. If it does cure the current problem you need to clean out the insides of the case and do the same thing to all plug in cards. You also need to clean out Heat Sinks to allow them to work correctly.

Col

If MS Exchange was functioning fine on your 2650 and the memory fault occured later on in its life, I have a feeling that most likly there might be a heat issue related to this. Memory failure ususally doens't occur. In solid state devices, they usually fail within the first week of their life, then last almost eternity, except for example taking outside causes... Heat is a big distroyer and it can also cause overflow/overrun errors. The 2650 also has some heat sinks on the internal chipsets. Some 2650 motherboards have the heatsinks 'glued' to the chipset chips. Some have a spring clip that is held in place by tap points soldered to the mb. Sometimes, through just basically getting old, and heat build up, and the constant tension on these tap points/holders of the spring clamp, they'll pull out of the mb. You may have a floating little metal tab on your motherboard.
After that being said, memory is hardware. Exchange is software. The bios of the 2650 will setup the hardware to function... independant of the external OS and the programs. So, software wont effect hardware, and vise versa. Unless of course there are direct machine code routines which MS wont/can't do because of the variety of hardware and bios platforms there are.