I will GUESS you have allowed a windows update between working and not working
Do not count on Windows to be fully up to date when it comes to device drivers Go to the vendor site to be sure you have an updated driver for your graphic adapter •nVidia Driver Downloads http://www.nvidia.com/Download/index.aspx?lang=en-us •ATI Driver https://www.amd.com/en/support There are also intermittent reports that the newest driver is not always the best driver due to driver bugs or compatibility issues, so you MAY need to try an earlier driver version
I will GUESS you have allowed a windows update between working and not working
Do not count on Windows to be fully up to date when it comes to device drivers Go to the vendor site to be sure you have an updated driver for your graphic adapter •nVidia Driver Downloads http://www.nvidia.com/Download/index.aspx?lang=en-us •ATI Driver https://www.amd.com/en/support There are also intermittent reports that the newest driver is not always the best driver due to driver bugs or compatibility issues, so you MAY need to try an earlier driver version