pull all pci cards and all memory, see if it gives a different code. add back 1 dimm, see if pc works. if not add back the other dimm. try to get past the 15 and get a code something like no video then add back the 560.
p.s. nice build. it should fly.
Here are other suggestions. http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems