I have a Dell Latitude E5250. When plugging in the AC adapter the only light that comes on is the power button light and it's blinking continuously. The other indicator lights are off. The system board has been replaced, no change. After the system board was replaced the battery indicator light came on and the battery charged, though the laptop would not power on when the power button was pressed. It would light up then go out. I've removed the battery and AC adapter, held down the power button to discharge flea power, no change. Followed Dell TechDirect directions to remove the battery and CMOS battery, then insert the AC adapter and power on the laptop, no change. I've tried known good RAM. I've removed all components including the LCD cable, no change. When the AC adapter is installed the power button light blinks continuously, no pattern, no other indicator lights come on. Any thoughts? I'm wondering if it's a video issue, bad Touch LCD?