Oh yes I forgot to give an update.
Anyway I got my Canon back...and yeah, they insisted its alright. So is my battery and my charger. Happy, I took my camera back, fixed on my lens, and on another day, took it out for phototaking again.
Interestingly, the very first time I used it after getting it back, the exact same problem struck again! The LCD and the camera froze after a shot, and I have to switch it off and on, but it refuses to turn on again. Furious, I removed the battery, the card, even the lens, and just left it on the bench while I went about using my other camera. An hour later of so, it worked again after replacing everything (the first time it went blank, it refused to work even after a day, although I did not remove the battery and card for extended periods).
It is working fine now...with no repeats of the dreaded sudden death. Pray to God it dosent happen again, for my warranty is ending soon!