If it is a DN372T, this is becoming quite common. You could try a maintenance reset where you keep the recordings, although this may well not fix the issue.
To do this:-
1. Turn the unit off at the rear.
2. Turn it back on again
3. Press the On button on the front and then press + and - buttons on the front of the box at the same time for 15 seconds.
4. Using your remote scroll down to Factory reset Keep recordings and press OK. If your remote does not work, you can use the + and - buttons on the box.
5. Follow the steps through the setup wizard and test your remote again upon boot up.
The box is no longer available, there are a couple of newer boxes, but they are not really recorders, as they are not dual channel. You would therefore have to have a look at getting yourself something else.
