Important: This method requires Windows to be accessible, if you are unable to boot in normal Windows mode. Please check for alternate methods, see footer of post.
You will see a blue screen with a few options.
Source: 7Tutorials for step-by-step screenshots
1. Open the Start Screen
2. Click the Power Icon
3. Hold Shift + Click on Restart
You will see a blue screen with a few options.
4. Choose Troubleshoot > Advanced Options > Startup Settings > Press 4 for Safe Mode, or Press for Safe Mode with Networking, or Press 6 for Safe Mode with Command Prompt.
Source: 7Tutorials for step-by-step screenshots