[Q] need help unrooting moto g 2014 topic

I'm trying to unroot my stock moto g 2014 (XT1068) so i can update it to lollipop (currently on 4.4.4.) I have the motorola drivers installed and i have adb and fastboot but im running into to countless problems, i'm stuck on 'waiting for device' after typing 'mfastboot.exe flash partition gpt.bin' into the command window. please help I have tried pretty much everything.