Well I looked at the specs of the board and it should handle those CPUs no problem. Now, when you returned the board, are you sure they sent a new one? I've sent stuff in the past and ended up receiving the same piece of shit. Now, I hold on to the part till I see the new part, the I trade.
If you take a look at your mother board manual in the jumper section, can you verify that it is set to auto-detect the CPU? That should be the default factory settings but you never know. If it is somehow manually set to run the CPU at ridiculous speeds, that could fry it quick. But I'm not sure just how quickly. You may even want to try to manually set the CPU speed using the jumpers if you want. If you head in that direction, make sure you do not exceed the CPU speed and end up in an overclocking situation. I'm not saying that's necessarly bad, but you don't want to add more variables when trouble shooting stuff.
Do you have proper fan/heatsink installed on the CPU?
Also, is the power supply adequate? Did you just dump a bunch of new hardware in an old system? You could have problems if there isn't enough juice to power all the components, but I doubt this would actually cause your CPUs to fry.
I tend to think the MB is the problem, but it could be other stuff. If you have acess to another PC that can support those processors, try in in them first. That will at least confirm that the CPU is not the problem.