I have an SSD only, Intel HD Graphics only, Ultrabook running on Windows 8 64-bit and after I turn it back on, after a long sleep of a few hours, the screen remains black even though the power is on (the fan and keyboard backlight are on). I have to force a shut down and switch it back on to use it normally again.
Hibernation and hybrid-sleep are turned off. It comes out of sleep of less than an hour just fine. Any advise?