Can anyone help?

Last night an RB450G on site stopped working. The unit is fed from a UPS so no power surge.

Anyway, it powers on with a single beep, then can see the LED indicating it's loading. All ethernet ports light up, then nothing. No ethernet light when plugged in to any of the lan ports.

Is there anything I can try?

Regards,
Matt.

Sounds like it fails POST. Connect a serial cable and reboot. You may need to reload the firmware via serial connection