On one of my client’s server running Windows Server 2012 R2, when you launched PowerShell it would immediately crash with the error:

and this would create windows events non-stop on the server as follows:

At first you think you have the famous PowerShell Virus (Poweliks) but after downloading the Symantec tool and running it, all was clean.
Second thing you try and do is patch windows. Running the latest CU for the server made no difference.
Running SFC /Scannow came back with “no integrity errors found”, so the operating system seemed okay.
Lastly, downloading Windows Management Framework and installing it resolved the issue with PowerShell.
The application launched fine with no more crashing.
Hope it helps.