hi, after installing windows 10 on my laptop, whenever i switch on with mains power , all i get is a black screen. to correct this i have to close down lid, as if putting into sleep mode, wait a few seconds and then open. this seems to do the trick but obviously doing this is a right faff every time. when its run on battery power, there is no problem. does anybody have any help or suggestions as to how i can correct this please