I have determined that there is absolutely nothing wrong with the laptop's display as when I start the system, the manufacturer's logo appears. This disappears as soon as Windows takes over control of the devices. As part of the troubleshooting, I attempted a system restore and as the update was being rolled back, the screen was functioning normally. However, the automatic update feature of Windows soon detected that updates needed to be applied and the display reverted to the previous state - i.e. Only an external monitor. Since then, a number of additonal updates have been received and applied and I am no longer able to roll back to a date prior to June 12. I have an Acer Aspire VN7-591G with intel i7 and 16 GB of RAM.