Create Safe Mode in Windows10
Nothing gets you out of Windows trouble like Safe Mode, which is why its inexplicable that you can no longer enter it by pressing F8 or Shift+F8 at boot. Although its still available in Windows 10, you have to boot into Windows first, then either restart holding the left Shift key or via an option within Update & Security in the Settings app. Neither method is helpful if your PC cant boot into Windows in the first place. 
You cant get around this, which is why its helpful to create a boot time Safe Mode option before trouble arrives. 
Hit Win+x and select Command Prompt (Admin), then type 
bcdedit /copy {current} /d "Windows 10 Safe Mode" and hit Enter. or Run As Administrator this batch file: Win10SafeMode
From the Start Menu type 
msconfig, 
run System Configuration in the results, and navigate to the Boot tab. 
Highlight the Windows 10 Safe Mode option you just created, tick Safe boot and select Minimal under Boot options and - if necessary - reduce the Timeout value so you wont be inconvenienced - the minimum is three seconds. Tick Make all boot settings permanent (in fact you can simply return here to delete the Safe Mode entry) and click OK.
You can repeat these steps, substituting suitable names in quotes at the Command Prompt, to create shortcuts for Safe Mode with Networking (tick Network rather than Minimal in System Configuration) and Safe Mode with Command Prompt (Alternate shell).
Source

Repair System Files
Run Commend Prompt (cmd) As Administrator.Type the following command:sfc /scannow
If message is a ?Windows Resource Protection found corrupt files but was unable to fix some of them?Type the following command:DISM /Online /Cleanup-Image /RestoreHealth
After this, run again sfc/scannow.
More about on Microsoft site

VPN on Windows 10: Selected Authentication protocol not permitted on the remote access serverThe remote connection was denied because the user name and password combination you provided is not recognized or the selected authentication protocol is not permitted on the remote access server
Setup your VPN as normal until you see the error quoted above.Open the Internet Options settings by typing it into the start menuClick the Connections tabClick your VPN in the list and then the Settings button.Re-enter your username, password and domain in the boxes provided.Click PropertiesClick the Security TabSelect the radio button titled Allow these protocolsSelect the checkbox titled Microsoft CHAP Version 2 (MS-CHAP v2)Apply the settings in each of the windows by clicking OK.

Backup VPN connectionsbackupset fname=%date:~-5,4%%date:~-8,2%%date:~-11,2%copy %APPDATA%MicrosoftNetworkConnectionsPbk asphone.pbk D:\%fname%_rasphone.pbk
restorecopy D:\%1_rasphone.pbk  %APPDATA%MicrosoftNetworkConnectionsPbk asphone.pbk

Enable biometrics login in Win10

There are a few million people suffering with long black screen bootups into Windows 10.  This can be directly related to ULPS (AMD GPU setting) being on, when on all laptops it should be switched off. See in the this video how to turn it off and bringing back the normal boot time of windows 10! No long blackscreen delay anymore.Search registry for key: EnableULPS and change value to 0.Fix video

Lost admin rights in Windows 10

When you lost administrator rights in Windows 10 for some unknown or uncertain reason, you have at least two options to get back administrator rights. Now, read this page for details.