Read the post above yours if nothing else, I hope you are leaving out a lot of what you did, but if not, you missed at least a couple steps.
Sent from my unleashed xt926.
I mounted...advanced wiped. Installed ROM, and that's it. Im already on 4.1.2 and unlocked bootloader. I dont want the theme so I only installed the ROM..when I go to reboot it gives me the no OS error.