Is it possible to use a NPN BJT as switch, from single power source?
When you close the switch, you are applying 5.2 volts across the base/emitter junction, which normally doesn't like more than 0.7 volts - this will destroy the transistor.

One way to use a switch and transistor to contol an LED is:







simulate this circuit &ndash; Schematic created using CircuitLab

R2 will limit the base current when thet switch is closed.  R3 pulls the base low when the switch is open, to ensure the transistor is not conducting.

Pressing the switch will provide base current through R2, allowing the transistor to conduct, drawing current through the LED and R1.  R1 limits the LED current to a safe value.