Vauxhall Astra information screen not working staying on

Hi guys, I have a 2007 platr astra. I noticed my central display screen starting playing up and going black when turn car engine on.. It then would come back on and work. Lately the screen now remains on even though the car is turned off and locked. This then In turns drains the battery every time. Do you have any ideas what could be causing this or how I fix this?