Now on the side of the modules you will see what looks like a lever.
Push the ever away from the module and then do the other side.
Try to remember how they come out as they need to go in the same way.
Once one stick is out then rerun the memtest with the one module. If it comes back good then you will need to remove the other module and put the module you first took out in it's place. Rerun the test.
Let me know what the results show.