switch led on/off

Grumpy_Mike:
Yes but the other end is to 5V

Pin 8 is an output to drive the LED.
The other end of the yellow wire is connected to where you would expect 5V, but there is no 5V on the breadboard power rail. Only GND, through the orange wire.

The way the button sits on the breadboard, all 4 corners are connected together.