To enable this policy setting, Run gpedit.msc and navigate to the following setting:
> Administrative templates
1. Double-click on Don't run specified Windows applications
2. Click the radio button Enabled
to enable the policy.
3. Click the Show
button next to List of disallowed applications
and add powershell.exe to the list and click OK
4. Test by attempting to run Powershell.
The information presented in this article has been taken from the Malware Prevention Guide