You might want to pay attention to this one if you run anything from Win 8 up because Microsoft in their infinite wisdom changed it so F8 to enter safe mode on your computer no longer functions at startup. This should get it back for you.
Just had a windows issue with my mouse and System Restore refused to work so I needed access to Safe Mode and couldn't gain access. So, after two hours of struggling to fix a simple Windows mouse issue, I managed to fix it and immediately began searching for ways to access Safe Mode again now that my mouse was letting me use it again.
1 – Click the Start button and type the letters CMD into the Search box. The words “Command Prompt” should pop up in the search results pane.
2 – Right-click on Command Prompt and select Run as administrator from the drop-down menu.
Note: Click Yes if a “User Account Control” window appears. You should now see a “Command Prompt” dialog box.
3 – Copy and paste the following line after the command prompt, then press the Enter key:
bcdedit /set {default} bootmenupolicy legacy
You should now see a message stating “The operation completed successfully”. If not, double-check the entry above and re-paste it after the command prompt.
4 – Click the X at the top-right corner of the window to close the “Command Prompt” dialog box.
www.ricksdailytips.com/enable-f8-for-safe-mode-in-windows-10/ 
Restore F8 On Your Computer
