Unable to retrieve system info using WMI in Windows 7

Using the example code provided here:

http://msdn.microsoft.com/en-us/library/aa390423.aspx

I have been able to retrieve hardware information using WMI on many versions of Windows (including Windows 7). 

The code is NOT working at all for one customer with Windows 7.

There do not seem to be any errors but the code does not yield any information.

Any suggestions or ideas ??

Thanks.