The Class subkey stores configuration data for classes of hardware devices.

Each subkey under Class represents a device class and is named by the GUID for the class. It appears as a 16-digit alphanumeric string within curly braces. These class-GUID subkeys store configuration data that applies to the entire class of devices, such as the class of all modems.

Within the class-GUID subkeys are four-digit numbered subkeys which represent particular devices that are instances of the class. These subkeys store data that applies only to that device.

Because the Class subkey is hardware specific, its contents vary widely. The Class subkey on your computer might look quite different from the attributes described in this reference.

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To determine the type of hardware device represented by a class-GUID subkey, use a registry editor. Click the name of the class-GUID subkey (it appears as a 16-byte alphanumeric string within brackets). The device type appears in the value of the first, unnamed entry in the subkey.

To display hidden devices, non–Plug and Play devices, and devices not attached to the computer (commonly known as ghosted or phantom devices), type set DEVMGR_SHOW_NONPRESENT_DEVICES=1 at the command line. Then, use Device Manager to remove or reconfigure these devices. Do not edit the registry. For more information, see Viewing Hidden Devices in the Windows 2000 Professional Resource Kit.

Many digits in the GUID are unique to your system. However, the three digits preceding the first hyphen are specific to the device class and are the same on all systems. For example, the three digits preceding the first hyphen in the DVD/CD-ROM drives class are always 965.

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Do not change any entries in the Class subkey or any subkey within it. These subkeys are configured by the system to be compliant with Plug and Play standards. Changing any data can prevent your computer devices from starting or operating properly.