HP Pro 3420 Maintenance & Service Manual page 109

Network driver does not detect network controller.
Cause
Network controller is disabled.
Incorrect network driver.
Network status link light never flashes.
NOTE: The network status light is supposed to flash when there is network activity.
Cause
No active network is detected.
Network controller is not set up properly.
Network controller is disabled.
Network driver is not properly loaded.
System cannot autosense the network.
Diagnostics reports a failure.
Cause
The cable is not securely connected.
The cable is attached to the incorrect connector.
There is a problem with the cable or a device at the other
end of the cable.
Network controller interrupt is shared with an expansion
board.
The network controller is defective.
Solution
1. Run Computer Setup and enable network controller.
2. Enable the network controller in the operating system
via Device Manager.
Check the network controller documentation for the correct
driver or obtain the latest driver from the manufacturer's Web
site.
Solution
Check cabling and network equipment for proper connection.
Check for the device status within Windows, such as Device
Manager for driver load and the Network Connections applet
within Windows for link status.
1. Run Computer Setup and enable network controller.
2. Enable the network controller in the operating system
via Device Manager.
Reinstall network drivers.
Disable auto-sensing capabilities and force the system into
the correct operating mode.
Solution
Ensure that the cable is securely attached to the network
connector and that the other end of the cable is securely
attached to the correct device.
Ensure that the cable is attached to the correct connector.
Ensure that the cable and device at the other end are
operating correctly.
Under the Computer Setup Advanced menu, change the
resource settings for the board.
Contact an authorized service provider.
Solving Network Problems 101