How do i recognize if my arduino chip is damaged?

Hello Arduino Community,

i am really new to arduino. i made the basics and stuff. recently i bought some tlc 5940 experiment with some more leds. I have the arduino uno r3 smd.

i was doing this simple project here:
as i closed the circuit the 2 leds in the circuit just lighted up for one moment.
Afterwards i cant get leds to glow. i changed them and build a simple circuit to test my arduino. the led on the 13 pin doesnt work and also when i connect some rgb anode to the 5 volt pin etc. But i can load sketches on the arduino.

What possibly happend here? i checked the circuit twice. is the tlc5940 broken, or some other parts? and how do i evaluate the source of the mistake? can i change the arduino parts easily? I hope the community can help a newb, it would be a pity when i have to buy a new one x(