In all previous version of Windows you could simply click on Shift + Right-click but on Windows 8 and 8.1 that is no longer the case.
To enable this in Windows 8
Bring up the run box and type in gpedit.msc
Now drill down to:
User Configuration\Administrative Templates\Start Menu and Taskbar
In the right panel look for Show “Run as different user” command on Start
It will say Not Configured. Double click on Show “Run as different user” command on Start and click Enabled
Close the Windows and open up elevated command pormpt and run gpupdate/force