Windows 8.1 still offers the old cmd.exe command window in some of its context menus. To change that and replace cmd.exe with powershell.exe, in Windows 8.1, right-click the taskbar and choose Properties.
Next, click the tab "Navigation" and check the third option.
Next time, when you press WIN+X in Windows 8.1, the mini start menu will offer "PowerShell" to you.
