Installed a track light 2 years ago. It has electronic transformer with auto reset. All was great for 2 years. Suddenly it was very dim making a high pitch noise. Removed all the lights and re installed. Now it has dim and flickering light from all the fixtures attached to the track.

It sounds like your transformer has gone bad. If possible check the voltage at the track and see if it correlates with the output of the transformer. But before you do that, pull all the bulbs out of the track.