joshua, for the longest time the consensus on iFixit is to replace the whole unit. Microwave ovens generate high voltages and dangerous amounts of radio-frequency radiation. Attempting to repair one is NOT for the amateur. I advise recycling it and getting a new one. On the flipside of this, you may just give us the serial number and we can try to find a common '''simple''' problem, but anything above that, you should leave to a professional.