TV/DVD player not recognising discs?

Hi I have small Technika TV/DVD player about 3-4 years old that won't play when there's a disc inserted -just keeps coming up with 'no disc' or 'disc error' on screen. I have checked that there's not one stuck inside & that I'm putting disc in correct way. I've tried lots of DVDs and all with same result-any suggestions pls? It started as an intermittent fault and now does it every time. Don't want to scrap it as my 9year old son would love it to play DVDs in his bedroom. thankyou very much