Just run this in a console.
@powershell -NoProfile -ExecutionPolicy unrestricted -Command "iex ((new-object net.webclient).DownloadString('https://chocolatey.org/install.ps1'))" && SET PATH=%PATH%;%systemdrive%\chocolatey\bin
cinst powershell
It installs the latest version using a Chocolatey repository.
Originally I was using command cinst powershell 3.0.20121027
, but it looks like it later stopped working. Since this question is related to PowerShell 3.0 this was the right way. At this moment (June 26, 2014) cinst powershell
refers to version 3.0 of PowerShell, and that may change in future.
See the Chocolatey PowerShell package page for details on what version will be installed.