Hi,
This seems a lot like what is going on to me.
Recently the windows 8.1 update got through, after a constant fight not wanting it a friend hit the accept button. And now I am at this same black screen with a pointer on it. Well that is where these problems started.
I entered into command prompt and used MSCONFIG to get the computer to start in safe mode. After this now I never make it to a login screen and my screen remains black, feels like a step backwards. And safe mode is now the boot option of choice.
Haven't found my way back to the command prompt screen or have anything that the computer will accept to access anything.
Wish the computer came with a windows 8 OS disk, if similar to past OS this should have been an easy fix.
Ethan
PS Ive tried re-booting while holding the shift key, no respons,I do hav a Asus G75 with an NVidia 770m and not an HP but it seemed to be a common suggestion on multiple threads on these forums.