pull out 1 stick at a time and check. that motherboard for 3 channel mode, the ram should be in slots 1,3,5, just an FYI.
Did the ram work after you put it in at all? you don't mention that or did it stop working aftering being moved?
Slots are the right ones, and I checked every ram individually but the problem is still there. (I put every ram in the first slot and checked with MemTest in turns)
Ram works fine, the only thing is this warning. Eg. MemTest find no errors and games plays well, but I'm worried about the alert sound.