Hi. My laptop when using battery has no issues. When I connect to electricity using original charger, it will go to a black screen after 5 minutes, 30 minutes or an hour or more - totally random. I have to do a forced shut down and restart which means any unsaved work is lost. I have returned the laptop to the shop I bought it from, but they cannot replicate the problem? I have since used other properties to use their electricity but still the screen goes after a time - BUT only when plugged into the mains? Please help!