My 2 year old 20D doesn't release shutter anymore. Became useless right in the middle of my trip to the NY Auto show. No Errors, no issues with anything else, it even displays 'busy' when clicking but nothing happens. I am not a professional so have hardly used it considering what one of my pro-photographer friend puts his one through. Has anyone had such an issue? If yes did it ever got resolved by canon's service center? Any info will be really appreciated.