but htc guys says tht the phone is out of warranty and they wud charge me for the further repair..
please help guys.. what do i do..? suggest sumthng..
From what I gather with what these two are saying to you, it sounds as if you need to go to HTC and PAY for them to fix your phone. It seems as if you've killed your phone, and nothing they can do/say will help you fix it.

HTC or your carrier should honor the warranty since the fault happened during the install of a stock HTC update with no indication of an install error until the reboot. You did nothing wrong. Sorry about that. 