ARCHOS AV700 TV WONT TURN ON BUT IF U HOLD DOWN POWER BUTTON

IF YOU HOLD DOWN POWER BUTTON IT START UP BUT SOON AS YOU RELEASE THE POWER BUTTON AGAIN IT TURNS OFF,
TO START IT WORKED THEN DIED WHILE IN USE THEN NOW ITS TAKING FOR EVER TO CHARGE AND WONT TURN ON,
the battery was completely dead plug in mains charger no lights or anything but power back to unit but with the same problem right back begining again so seems to charge battery very slowly please help im new to these thanks