Sounds like it could be a disconnected door switch, or a blown H.V. fuse. Which would mean either your Magnetron, capacitor, or diode is faulty. Hence it making all the right noises but not cooking. I seriously doubt it had anything to do with your cleaning method. The magnetron is probably the most expensive part out of all those possibles. Get someone out to look at it for you, and then weigh up the cost.
Jon
July 2007