when you tried to start powershell and the window opens and closes immediately.
Open a cmd and start powershell by calling powershell.exe
C:\> powershell.exe Windows PowerShell terminated with the following error: Could not load type 'System.Management.Automation.Runspaces.EarlyStartup' from assembly 'System.Management.Automation, Version=220.127.116.11...'. or "System.Management.Automation.Tracing.PSEtwLog' threw an exception"
This error occures if Windows Management Framework 5.1 is installed and not the previous Verions 4 or 5.0 on which it depends or .NET Framework is corrupt.
Uninstall Windows Management Versions 5.1 and 5.0 and install install the latest 4.xx Version of .NET Framework , then Windows Management Version 4, 5.0 and 5.1.