How to Start Windows 10, 8(.1), 7 or XP in Safe Mode

https://www.tweakandtrick.com/2013/08/windows-safe-mode.html 

Windows 10, Windows 8 and Windows 8.1

The F8 key method does not work on Windows 10, Windows 8 and 8.1. Hence, getting onto Safe Mode requires the following steps:-

If your PC is working properly:
1) On the Windows Start Screen/Menu, type Advanced.
2) Click on Advanced startup options.
3) Under the Advanced Startup heading at the bottom of the General Settings screen, click on Restart now.
4) Your computer will restart and you will be taken to the Advanced Startup Options menu. To easily reach this menu, on Windows start screen, you could choose restart while holding the Shift key.
5) Click on Troubleshoot and then on the Advanced Options button.
6) Now, click on Startup Settings.
7) At the Startup Settings Screen, click on Restart.
8) Your computer will restart to Advanced Boot options from where you can choose a Safe mode option based on your need 

If your PC is not working properly:
Windows monitors your PC's startup for problems and when an error is detected, it automatically takes you to the new Recovery mode with the message "Recovery. It looks like Windows didn't load correctly." In this case:-

1) Select Advanced Repair Options and then click on Troubleshoot.
2) Click on the Advanced Options button.
3) Now click on Startup Settings.
4) At the Startup Settings Screen, click on Restart.
5) Your computer will restart to Advance Boot Options from where you can choose a Safe mode option based on your need

registry editing has been disable by your administrator

Enable Registry Editor using the Group Policy Editor

1. Click on Start. Go to Run. Alternatively, use Windows key+R keyboard shortcut.
2. Type gpedit.msc and press Enter.
3. Navigate to User Configuration/ Administrative Templates / System.
4. In the work area, double click on "Prevent Access to registry editing tools".
5. In the popup window, encircle Disabled and click on OK.
6. Normally, Registry Editor will be immediately accessible. If it is not, restart your PC.

https://www.tweakandtrick.com/2011/04/enable-regedit-registry-editor.html?m=1