First I would ask you to check all the HDInsight specific services are running in your cluster as shown below after restart:
If any of the service is not started, start it. Next what you could do is format namenode name by using command and it sould
hadoop namenode -format
After you format you will see new name node folder created @ C:\hadoop\hdfs\nn with some files in it. If you still see the problem contact HDInsight Support forum here.