Answer to "My Dell inspiron 15R display goes black after using for some time?"It sounds like your back light on your LCD screen is going bad or possibly the connection to the cable is loose! Try hooking up another monitor to it and see if you get video on that OK. If nothing appears on the other monitor try holding FN key and hit F1 to toggle thru ouputs until it shows. Amazon.com has a replacement screen for about $52.00! I just ordered one today for a friends 15R that was showing a "Black Screen". Actually you can see objects on the desktop under a bright light. The LED Back light is what makes the screen bright. There is no LCD Inverter on this model, so replacing the screen will likely fix it! This particular laptop worked fine with external monitor! Hope this helps! Plenty of Videos on Youtube showing how to change the LCD in about 1/2 hour! Good Luck!