I have an LG hard drive. I just bought a new monitor (HP) because my old one was going to a black screen and I couldn't wake it up. I tried another acer monitor that works with another computer and that one worked with my computer. So I bought a new HP monitor and this one is going into sleep mode too. When I start my computer the screen works fine and opens to my desktop, but after 10-15 minutes the screen says sleep mode and when I move the mouse/hit space bar nothing happens.