Sometimes routers die. My general reaction to router problems is to toss the thing and buy a new one. However, if you don't want to do that I'd suggest trying to update the firmware to see if it helps.

If it helps with the wiring, I've been very pleased with my powerline extenders. The speed through that thing is very good from a wired connection, and I also moved a wifi emitter onto the end of it as well and it's holding up very good wifi speed as well. If you don't mind spending some money, I give those devices two thumbs up for solving networking issues without running more cables.