Asus motherboard problems

So I have a maximus V gene and I first got the b2 error and it would not post so i sent it in for the warranty, It came back and I put it back in the case a plugged everything back in and I get the same error when I have my gpu in and when i dont i get the d7 error. I'm going to send it back in again if I can but I would like to know if there is anything else I can do beforehand. I've unplugged all of the hard drives and there is only one ram stick in and no gpu. 

my specs are 

maximus V gene

gtx 660 ti 

8 gb corsair vengeance ram


barbone on a bench > single stick of ram in the slot with the greatest distance from the cpu. > no hdd's etc plugged in. > just a keyboard and monitor plugged in. > double check every connection - the 24pin, the 8pin etc. make sure that that single ram dimm is in properly. > clear the cmos > power on

if it boots into the bios then is a process of adding in each component. if it doesnt swap out the ram > that fails > make sure that the pins havent been damaged when you installed the cpu