There's a 3 key shortcut already.
Note: do not keep each key pressed when you press the next one. Press one, release it..press the next, release it..etc..Windows Logo Key
If you notice when you hit the Windows Logo Key (and the Start Menu comes up), the u
rn off computer" is underlined. Pressing U
does the action that has U underlined (like hitting Alt + some letter
in any application). Hit U again, the u in "Tu
rn off" is also underlined, so it performs that action (shutdown). Pressing R
here instead of U
would do a Restart.
Note: The letters you have to hit to do this vary by version of Windows....the way you access "Power Button Actions" for Vista and Windows 7 are slightly different.