Just try booting up with one stick of ram in there.. might force the bios to realise there has been a hardware change.
Only reason I mention its worth a try is that I had a similar issue back in the day when i was overclocking my 5820k.. tried bios reset and battery with no luck.. Starting with only one stick of ram in there instead of the 4 seemed to kick the bios back into action.. similar to how the guy mentions it above..
No idea if it will help but worth a shot before you RMA the stuff.