We once had a DISH receiver that was non-responsive at times, so we called DISH support. They talked us thru a change, and gave us codes to enter using the remote. Afterwards, the spare remote could no longer work the receiver, but the problem was solved.
The next time this happened (with a different receiver), the solution was to double-tap the buttons. Before we learned to double-tap the buttons, an infrared/wireless extender was used to boost the remote's signal.
You should also try separating each device by a distance of three feet. There could be radiation from the receiver, or even another device in the setup, that could be causing an odd problem (which might also kill a VHS recorder, but I'm thinking of a DirecTV receiver).
Also, poorly shielded cables (the cheap ones), might pick-up interference, and that might hinder operation of your receiver/DVR.