To try this out, go to the run box and type in something (cmd, for example)

Now instead of hitting the Enter key, use Ctrl+Shift + Enter. You will be prompted with the obnoxious User Account Control dialog… but it will then open up a command prompt in Administrator mode.

Source: http://www.howtogeek.com/howto/windows-vista/run-a-command-as-administrator-from-the-windows-vista-run-box/