One thing to "try" before throwing it out. Reflash the router firmware (with the same firmware if nothing is newer). If it won't let you because it's the same version, try going back a version and then upgrading. The purpose here is to erase and reprogram the flash.

I resurrected a couple of modem/router type devices before. Seems the flash can go "bad" (and I've experienced this at a chip level in the embedded work I do).