IsGenuine returned TA_E_COM in guest user

Hi, I am using Windows 7. TurboActivateNative.INSTANCE.IsGenuine(....) worked correctly in admin user. But it doesn't work in guest user. I re-enabled WMI, but anything changed. Is there anyone knows issue? Please help me

TurboActivate works flawlessly on all Admin / non-admin "regular" accounts. However, "Guest" accounts are a special beast because they're so limited. First you'll have to give the Guest account permission to talk to WMI. Here's a good place to start: http://community.zenoss.org/thread/12048