You connect a USB keyboard to a Windows Vista-based computer. Then, you view the devices on the computer in Device Manager. When you view the Driver tab of the parent USB host controller, you notice that you do not have an option to disable the device. The Disable button on the Driver tab of the parent USB host controller appears dimmed, and it is not available.

If you disconnect the USB keyboard from the computer, and then you update the view in Device Manager, the Disable button is available.