Rebuilding Performance Counters

1. Check the wmiadap.log file in system32\wbem\logs for details to see if something doesn't look right
2. From a command prompt, run: wmiadap.exe /c
3. Then run: wmiadap.exe /f

Windows Management Instrumentation (WMI) uses AutoDiscovery/AutoPurge (ADAP) to build its internal performance counter table. This causes a clear, then a force rebuild. If that does not work, you can try this command: winmgmt /resyncperf

For more information, here's a link to more information on wmiadap.