a new matching pair crashes my comp

[MuddyMudSkipper]

I have a Falcon V with a EVGA NForce 680i motherboard with a Intel Core 2 Extreme QX6850 quad-core. It has and still does run great without problems. I have had a pair of Corsair 8500C5Ds and have never had a issue. I just got two more from somebody who said they tested them using MEMTEST86+ v4.2 and said they were fine. When I installed them my perfectly running computer, it would no longer run. Blue screen, crash, restart... I pulled them out and it runs fine again. I pulled the good ones and installed the other ones one at a time and neither will work.

They are the exactly the same saying this below the model# "XMS2-8500 2048MB 1066MHZ 5-5-5-15" Then comes the only difference, the good ones say "2.10v vert.2 10140510" and the bad ones say "2.1v vert.1 08241025".

Is there some reason why the ones I just got should not work when the others have always been flawless? Clearly it has nothing to do with any setting on my computer when I have a matching pair that work just fine. Right? Are these others (which were said to test fine) no good or could it be something else?

And just to be clear, I can't run a memory test on these 2 bad sticks as when they are in my computer it won't run!

Do I need to return these sticks or what?

Thanks for your help!

PS I did open a RMA case but I got no reply, so here I am bugging you.

[RAM GUY]

If you purchased the Modules from another user I am sorry but there would no warranty from us and they would have to go back to the reseller.

But they are a different version so I would try and reset the MB BIOS with just the new modules installed and then go to BIOS setup and load setup defaults and set the tested settings on the modules and test them again with http://www.memtest.org.