Step 1 Go to Safe Mode (may be with networking) Click on Windows (Start) button and in start search box type in services.msc and then in menu right click on services and click on "Run as administrator"
Step 2. Double click on "Windows Management Instrumentation" and click on STOP button and stop this service
Step 3 Go to c:\windows\system32\wbem\repository and rename the repository folder (if Vista on a different lettered partition alter that accordingly)
Step 4. Then go to "Windows Management Instrumentation" and click on START button and start this service
Step 5 Restart the computer and issue will be resolved