Ok replacing the lamp is easy, simply take apart the case halves, locate the lamp,undo the fixtures, unplug the lamp from the circuit board, do NOT touch the lamp, use gloved hands. plug back in again, reafix the attachments and put the case back together, now test the unit.
You must be sure it is the lamp though, and Not the circuit driving it,as this often goes faulty, and NOT the lamp. you need to test the lamp with a meter and see if it has a reading if open circuit, it's faulty, if not, then it's the driver, or even perhaps the USB interface, or whatever controls it. I have given you a service manual, above, this will give you an idea.