[q] big problem can't install stock rom topic

Hi I HAVE A BIG PROBLEM
I have a moto g unlocked phone. I would root this phone but it failed with rooting. Now i would relock the bootloader and install the stock rom. As install the stock rom all file install but the system files aren'T install. It says,,failed to validate system image,,. i reboot it it says that is unlocked, turns off, turns on with the unlocked message and then come a android with a red triangle Now my question is can i install with usb otg cyanogenmod or stock rom

PLEASE FOR HELP

PS: i can go to the fastboot