If WMI service is not working on your Windows system, you can use WMI Diagnosis Utility to troubleshoot the problem. WMI Diagnosis Utility is A utility to help system administrators diagnose and repair problems with the WMI service.

Windows Management Instrumentation (WMI) is the infrastructure for management data and operations on Windows-based operating systems. You can write WMI scripts or applications to automate administrative tasks on remote computers but WMI also supplies management data to other parts of the operating system and products, for example System Center Operations Manager.

You can download it from Microsoft. Read more on how to use WMI Diagnosis Utility at TechNet.

Also see WMI Control Panel is not working.