I had my RHEL 5 guest hang on boot before nash. Attempting to reinstall also hung after LILO on a black screen with a blinking cursor. Re-inserting kvm_intel with emulate_invalid_guest_state fixed this.
Can you try kernel-3.12 from rawhide on the host? Also please provide: /var/log/libvirt/qemu/$vmname.log sudo virsh dumpxml $vmname (if using libvirt)
There's a kernel (kvm) bug tracking similar issues, which claims that 3.13 should be all fixed here (which is in rawhide). Duping to that *** This bug has been marked as a duplicate of bug 967652 ***