Using the WMIDiag Utility - SMS was one of the first applications to take advantage of WMI. At one time, SMS was often the only WMI management application running on many Windows machines. In those days, it was a common practice among SMS administrators to simply delete the repository when WMI errors were detected, and then restart WMI to re-create the repository. This is no longer a safe practice, because many applications depend on data stored in the repository. Moreover, WMI errors can result from many other problems in your environment and may have nothing to do with WMI itself.
Rather than deleting the repository, you should obtain the WMI Diagnosis Utility (WMIDiag) from the Microsoft download site (http://www.microsoft.com/downloads/details.aspx?familyid=d7ba3cd6-18d1-4d05-b11e-4c64192ae97d&displaylang=en, or go to http://www.microsoft.com/downloads and search for WMIDiag). WMIDiag can help you diagnose most WMI problems, and in many cases it provides detailed instructions on how to correct those problems.