If Windows PowerShell has stopped working & is not opening or launching, due to Restrictions in effect, No app associated with it, etc. see this post.

This warning message generally occurs when users try to execute an application the system administrator blocks by making amendments in Group Policies or Windows settings.

Fake IT support sites promote malicious PowerShell "fixes" for common Windows errors, like the 0x80070643 error, to infect devices with information-stealing malware.