My microwave did not heat very well one night and then the next morning it would not heat at all. I also remember resetting the clock twice the week before it broke. It also began to make a slight noise. The panel lights all worked. I turned off the breaker to the microwave and then turned it back on later. The part of the panel where the time is then showed strange characters on it. Does anyone know what might cause this and if it is worth fixing. I think it is a little over 5 years old. I cannot fix it myself but I would get repairman if it might be something small.

Thanks for any help.

Could be a number of things.
Unless it is a top of the line unit, microwaves are now throw away.
The labor alone to just open it up and take a look is often more than 50% of the cost of a new unit and it is not worth while putting that many dollars into it.