Reinstall the firmware on a router without the setup CD ...
https://kb.netgear.com/1984112.11.2021 · In the File field, browse and locate the firmware file that was downloaded earlier. Turn the router off for 10 seconds and turn it back on. While the router is still in the boot process (ie. Power light is still 'amber') click Upgrade and wait for the process to be completed. Once the process is complete, the power light will turn steady green.