i'm not sure if this is a cause or not, but it seems when i try to wake my phone with anything other than the power button, i get a black screen, but the menu/back buttons light up. i haven't found any way to get the screen to come back other than pulling the battery. would something be causing the phone to do this when pressing the physical button to wake it?
I never thought of holding the button... I just got frustrated.
Everything you just explained happened to me and I can reboot after holding down the power button.