hmm should have known that would be to easy. Go into bios and set all ram settings to default if your not sure what to do there should be something that says restore bios to safe settings that will serve the same purpose. Then test each slot with one stick and see what happens the repeat each slot with the other stick. At that point you should have found the problem be it the slots or the sticks. Do all slots both times in case there is more than one problem.