Does one need to disable Powershell completely? And is this even desirable or possible on Windows versions greater than 7? On my Windows 7 machine, I started a Powershell console w/administrative privileges and ran
Set-Execution-Policy -Scope LocalMachine Restricted
which disables running PowerShell scripts execution in any context. Individual Powershell commands are still allowed, of course, so Powershell-powered malware hasn't been entirely neutered, but this is a significant protection I think.