If you run in to problems with your PC or need to troubleshoot hardware problems, there's a very good chance that you'll want to use "Safe Mode". This boots Windows 10 using minimal drivers and services, plus it prevents any of the usual startup applications from loading.
This article assumes that you can already boot in to Windows 10 - if not, please use the recovery media to attempt to boot in to safe mode. If your system fails to boot twice in a row, you will also be presented with the following options which will allow you to boot in to safe mode. If you would like to add the option to have the F8 safe mode menu appear on boot, please read this article.
To begin, Shift + Click the Power Options > Restart button on the start menu, start screen or logon screen (this will immediately restart your PC, so save any work!):
Once the PC has restarted, you'll be presented with the boot menu. Select Troubleshoot to continue:
Now click Advanced Options:
Then click Start-Up Settings:
Now click Restart to reboot your system once more:
Finally, choose the type of Safe Mode that you'd like. You can boot to Safe Mode (without network drivers), Safe Mode with Networking (includes network drivers), Safe Mode with Command Prompt (opens up a command window by default).
Unless you're having network specific problems, you'll most likely want to boot to Safe Mode with Networking so that you can access the internet. Press the corresponding number on your keyboard to boot in to Safe Mode: