can I reset portable dvd player?

I have a portable Alba DVD which powers up, the screen comes on great bu 2 seconds later the screen just goes blank as if there's no power. The sound of the dvd still continues to play, and oddly enough if you switch the player on while holding the play (or indeed any!) of the buttons on the dvd player, the screen remains on until you release whatever buton i'm holding. I'd be grateful for any knowlege re. this annoying prob. Thanks