How to replace the light bulb in a microwave?

firstly Unplug the microwave and check the cooking area, in case cover-plate is there bulb is right there turn it quarter, later turn it to the left and pull the base straight out. if If you can't see a cover-plate on the interior wall turn microwave and look for cover on the back. take out the screw to see the bulb. pull out the old one and insert the new bulb. Screw the cover-plate back on

Open it uo from back ward,and bring out all parts from in.Then after change it!

 interestingly  MICROWAVES come with INSTRUCTION MANUALS

  if one does not HAVE the instruction manual

 one can go ON LINE  ( one obviously has computer access its the means of how one posted this  question  )      type in model and  find it available to READ  on line

 to get DIRECT INSTRUCTION for that model

 of HOW to change  the  light bulb  for that PARTICULAR  MODEL

   there is no good reason to  rely  on   2nd or 3rd hand   directions

  go to the SOURCE  the manufacturer

 thank you for the question

Im mine theres a round cover inside the microwave where you set you food.  it has 1 screw an you remove the cover to acess the bulb.

Depends on the microwave. On ours, you simply turn the power off, remove the cover over the bulb, change the bulb, replace the cover and turn the power back on.

Not as dumb a question as some answers here imply. Every microwave has different type of bulbs and different locations within the microwave. MINE, you have to remove the outside framework, and it's a nightmare. You will have to consult the manufacturers manual, which if you haven't got a hard copy of, you can get online. 

Remove faulty light bulb and replace it with a functional light bulb.

It is not rocket science.

maker's website. ask in support section. this must be done carefully to assure that microwave radiation can not leak

There's usually a small removable panel inside the cavity. Remove it carefully and replace it carefully. It's important to make sure that radiation cannot escape from the cavity. If yours is the type where it's necessary to remove the outer case, get a professional to do it. If the case is not refitted correctly, it can be lethal.

Read the instruction manual. If misplaced, see a copy on the manufacturer's website. Golden rule is to disconnect the oven from the mains before doing anything. On mine there is a little door inside that opens and the lamp is behind, others need to take the back off, or the top cover, a job for a professional.