help! need to unroot!

[anthrpicdecadnce]

My phone crapped the bed. i'm going to assume the gpu blew, because i lost my display and it wont mirror out to hdmi. whatever the case, i need to unroot so that verizon wont try to pull any funny stuff and charge me for the warrenty replacement they gave me. however, when i try to fastboot, it fails immediately. i get the flash failure at 1/18. also, psouza4's one click doesnt work. it deletes data and cache, but cant access anything else. it's not bricked or anything. i can still power it on as long as i have some battery. and i'll feel it vibrate when i press 'search' to continue (safestrap) and it vibrates quickly afterwards (successful boot). on top of that, it will then allow me to access my phones internal memory and such. i can pull stuff from /system. but i cant simply delete superuser. so how can i hide my rooting? i know my phone didnt crap the sack cuz of anything i did. i just dont want to have to pay for a hardware failure that clearly wasnt my fault. does anybody have some insight into this? this is driving me crazy! thanks in advanced.