Abstract: A power adapter warning system includes a computing device that has a display screen and that is coupled to a power adapter device and at least one peripheral device. The computing device initializes and, in response, detects the power adapter device. The computing device then determines that the power adapter device does not provide sufficient power to complete a boot process and, in response, prevents power from being provided to the peripheral device(s). The computing device then performs the boot process such that the display screen is available for displaying information, and provides a power adapter warning message for display on the display screen. The peripheral device(s) may be connected to the computing device via USB connectors, and power may be disabled to the USB connectors to allow the computing device to perform the boot process using power provided by the power adapter.