Recently I tried to install CM10 and I forgot to clear the storage and now my phone is basically screwed. Ive tried to install 2 different ROMs and neither worked.
This happened before with my Optimus S. I fixed my problem by downloading a official software update. So just go online go to HTC's website and transfer it to an sd card and flash the update and you'll get stock rom with no root. I dont know of any other way . Good luck !