Since the light comes on and the turntable rotates, I would suspect a bad magnetron, a loose connection at the magnetron, a failed high voltage transformer, or shorted high voltage rectifier diode.
If it's less than one year old, it should be fully covered under warranty.I'd suggest contacting the manufacturer to get it fixed free.
Ifit's within the magnetron portion of the warranty (usually 5-9 years)but out of the original full warranty (usually 1 year), then yourmanufacturer will cover the part cost, but not the cost to visit you orthe labor charge to do the work.
If you or a friend want to work on it, please see these links first:http://www.microwavedisplay.com/safety.txt
Here are some links you or someone you know can use (in order given) for test help, but read the safety warnings first:http://www.gallawa.com/microtech/diode.html
(if it is NOT shorted, it's probably fine) http://www.gallawa.com/microtech/mag_test.htmlhttp://www.gallawa.com/microtech/xformer.html
Thereshould also be a "mini-manual" hidden inside the unit behind thecontrol panel or hidden on the left side behind the grille, which isvery helpful
when troubleshooting & testing.
For Frigidaire models, you can usually find helpful exploded view diagrams and order parts
by entering your full model number here
Or you can find your nearest Frigidaire/Maytag-authorized servicer here
You can visit Daewoo online
or call them at 1-800-323-9668 or 1-800-553-4355 to find parts or findyour nearest authorized service center to have them do the work.We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.