How to Resolve Exclamation Mark Driver Error with SM Bus ... - Dell
If you have recently reinstalled Windows XP on a Dell desktop or laptop, you may notice an exclamation mark or a yellow question mark in your Device Manager listed under "Other Devices" as SM Bus Controller . This indicates that the System Management Bus driver is missing. This component is essential for the motherboard to communicate correctly with power management features and voltage regulators. dell sm bus controller driver xp