I'm wondering if a W10 update has enabled the on-board graphics and disabled the stand-alone card? In Device Manager is there any reference to an integrated card and if so has it been enabled? If you find this are you able to right click and disable it?
Have you tried running the Windows 10 troubleshooter?
Type “Troubleshooting” in the Search bar and press Enter. Click on “View All” in the top left corner. This will display the list of troubleshooters which are built-in in the computer. You can click on Hardware and Devices from the list and you can run the troubleshooter.