Technosonic DTR110 TV/DVD resetting?

My 4 year old daughter got hold of the remote control a year ago and the DVD player hasn't worked since. She's done it before, two years ago, changing the zone setting from UK to something else so it wasn't playing UK DVDs, but I got that sorted by reseting the DVD player (I had picture and the machine was "communicating" with me so I could input instructions that I found on a help website) and everything was working perfectly.

Now the TV works perfectly only when the DVD is not in use and the unit is connected to a Freeview box, but if I put a DVD in all I see are just some running coloured lines.

I'm hoping someone would tell me if I can reset it again and how. I cannot find that website again... perhaps someone here will know the answer. I promise never to leave the remote control under her hands again... if only I could mend the unit now.