I have just bought a DV7 that was claimed as not working on ebay. When I received it, I cleaned it of dust and replaced the hard drive with an ssd. It does this problem with the old drive also. But while booting it is just a black or gray screen until it gets to windows. (The boot time seems to be very long, about 30 seconds to a minute) If i connect a external display thru VGA or HDMI it shows it on that monitor but not on the laptop screen. I've tried re-seating the screen connector and cleaned the connector. In windows there is no problem. you can move it around tap on it and never a flicker.