I've been having some issues with WMI on my laptop over the past couple of weeks (the symptoms of which have been strange WMI repository messages, inability to run WMIC or scripts, machine running slower than usual etc.). I didn't really want to have to re-install or repair Windows to fix this. Fortunately I found this very helpful article on resetting and re-registering the WMI services.
This included the following commands to re-register all of the WMI components:
cd /d %windir%\system32\wbem
for %i in (*.dll) do RegSvr32 -s %i
for %i in (*.exe) do %i /RegServer