when looking for info like this, you have to deminish some logic and think outside the box, like there is a class win32_DiskDrive, but there are also some aditional ones like PhysicalMedia, PhysicalDevice, DiskDrivePhysicalMedia, StorageDevice.
Not all classes exist on all machines, it depends which ones are instanciated when the hardware is installed. Alot are standard, defined by windows, but if you buy a pre-built machine from a mainstream manufacturer, alot of the time, especially for business PCs, an extra eprom chip is put on the MoBo to create, and populate aditional classes, this is mainly for custom network-wide manageability tools.
Another little tip... if you don't know the class you are looking for.....
Click Start > Run
Type wbemtest
Connect
Replace root\default with root\cimv2 then press connect
Click "Enum Classes"
Leave the Superclass name blank, and select the "Recursive" radio button and hit "OK".
All the classes are listed and you can search and select to open straight from there, then as before, open, select the instance, and voila.
ALSO
A class, such as "Win32_DiskDrive", is like any other object oriented, class driven process, just like OOProgramming. It utilises Inheritence. For example, the Win32_DiskDrive does not query the disk for the Disk's name, it inherets it from Win32_PhysicalMedia, along with many other properties, it then adds it's own properties which are dependent to the class, these may then be inhereted further down the chain by another class such as Win32_LogicalDisk, which looks at partitions (so Windows Drives - C:\ and D:\ being on the same physical disk, but being seperate logical disks). There PhysicalDevice name is the same for both logical drives, but there is no point querying the hardware twice, so it inherets the data from the natural superclass.
Hope this helps
Neil J Cotton
Technical Consultant
Anix Group Ltd
