Bill has been getting DLL errors. Leo says that the only real way to solve this is to do a complete Windows reset, which is really easy in Windows 10. Bill can just press the Start button, then select Settings > Update & Security > Recovery. Under "Reset this PC", he should select "Get Started".
Bill should restart his PC to get to the sign-in screen, then press and hold down the Shift key while selecting the Power icon, and select "Restart" in the lower-right hand corner of the screen. After his computer restarts, he can select Troubleshoot > Reset this PC.