I left my laptop on overnight in the morning it was off so i start it and it runs for around 40 mins then turns off with no warning. I thought it must be something todo with the battery or charger so i swap them for spares. Then try start it then runs for around 10 mins then stops. So i try starting without battery and the front orange light doesnt come on and it wont start. I try again with battery in and it runs for around 5 mins then stops. Any ideas now it won't start at all. Has motherboard died ? Is it fixable or replaceable?