how can i fix my goodmans gtv34rdvd?

Hi
I have exactly the same problem. I have an old and extremely reliable Yamada multiregion DVD player (recommended as a best cheap buy by me) that will play absolutely every disc I put in it. My GTV34RDVD refuses pont blank to recognise any discs, DVD (shop bought or not) or otherwise. put them in the Yamada they work, put them in the Goodmans and not a sossidge.
Any hints and tips gratefully received (but not "bin the thing")
Cheers

ErrorMessage
September 2008