Any ideas on what might be the problem with my router?

I have to unplug the power my upstairs router so that I can get internet downstairs. It seems to be getting worse. It used to be that I had to do it occasionally but now it has become an everyday affair.
Is it a router or a cable problem? I think it is the router because the upstairs computer is active at all times regardless of the whims of the router. ‘Course, it is wired in directly to it.
Is it time for a new one?