How to Fix Restart Unexpectedly Error.

As Per the below issues 

Install Windows

The computer restarted unexpectedly or encountered an unexpected error. Windows installation cannot proceed. To install Windows, click "OK" to restart the computer, and then restart the installation.


Press Shift + F10 Button. 

The command prompt will open.

Type: Regedit

Select As per below mentioned path and Picture. 

HKEY_LOCAL_MACHINE\SYSTEM\Setup\Status\ChildCompletion

The default value of Setup is 3. If the issue has occurred setup value is 1 --> change to 3 value.

Regedit


Double Click on Setup.exe or Right click on setup -> click on Modify  --> Set Value to 3. Click OK Button.

As per the below picture.


Regedit


Restart the System.

Windows OS will create a new profile(User). 


If any doubt, Pls share ur question in the comments.