I have bad news for you. It is a corrupt Microsoft update. I had the same thing today at work. We have the Dell/Microsoft pro support and they spent over 2 hours today trying to get it at least to the boot screen with no luck. We even have the recovery files but it won't even load those. I was told that they have seen a rash of this problem on Win 7 & 8 the last couple days and they were only getting about 50% repaired without a clean install since it won't get past diagnostics to even start loading Windows.
My system has a solid state boot drive and a standard hard drive. They are sending a tech out Monday with a fresh recovery disk & a new SS drive. I'll report back as to the result. All I can say is I am sure glad we have automatic back up on an external hard drive and 2 cloud services.