Matsui DVD/TV combo - on countdown mode can you help?

Hi, I bought a DVD/TV combo (Matsui) second hand. It worked fine for a week and now all I get when I turn it on is a 5 minute countdown on the screen. Nothing I press on the remote has any effect. I can't even open the drawer anymore. I woudl appreciate if anyone can offer me advice or even tell me where to look for an answer. thanks for reading