router problems

So last week I switched off the electricity in my computer room, now when I switched it back on my router is acting strange. The power icon is flashing red and every 4th or 5th blink is green. Sometimes the WLAN icon is flashing green and internet red. And obviously the router won't connect to the internet. The router is also making a high pitch noise. I couldn't access the router settings using my browser. The Windows built-in troubleshooting said the ethernet cable is broken, changing it didn't help.

Switching the phone cable and the adapter didn't work. My backup router did connect to the internet but I only want to use it as a temporary solution.
The possibly bricked router is a Zyxel p-660hw-d1.