I have a new T3i (~200 images, bought in November) that stopped functioning properly today.

I was taking pictures outside in bright sunlight. My 55mm was attached and I changed lenses to the 100mm macro. The camera was on during the switch, which i've never done - i always turn it off first. Once the macro was attached i clicked the live mode to exit the setting screen on the LCD and view the scene live. At this point nothing happened. The setting screen stayed.

With no luck, I attempted to turn the camera off and turn it back on, but this only resulted in the camera not turning on. It is a brick at this moment. 

I checked the battery level a minute or two before this happened. it was full.      

Any thoughts? Thank you