How to get PC Model type?

Is there a function or some method to get a PC's Model type? In my case this would be "OptiPlex 780". Until now i queryd 开发者_运维百科it from WMI (WIN32_Computersystem), and it worked in 99% of the cases, but sometimes, it couldn't retrieve the Model. So WMI isn't an option for me. I'm looking for an other way. Does anyone has an idea?

Thanks.

According to Microsoft's documentation, Model must always be filled in:

Model

Data type: string

Access type: Read-only

Product name that a manufacturer gives to a computer. This property must have a value.

Perhaps the times it doesn't work is when you're logged in to a non-administrator account?

Most access to WMI is restricted to Administrator accounts but non-Administrator accounts have some access on the local computer.