What if the black screen doesn't start when you upgrade Windows 10?

After the start of the black screen cause analysis:

Graphics driver compatibility problem caused (dual graphics card) We can solve the problem by WIN10, the following steps:

1. In the WIN10 system into the "Troubleshooting interface" then we click "Troubleshoot---Advanced options" step by step into;

2. Select the "Startup settings" option in the Entry interface (power-on setting)

3. After entering safe mode, try uninstalling or reinstalling the video driver.

4. If the above method does not I can choose System Restore point, let the system back to the compatibility problem before, if not restore we can reinstall the system to solve this problem.