Here's a couple of tips....... (be aware my methods are not the only way to do things, just they're just my way)
"Show Desktop" does not minimize anything. What really happens is a full screen, borderless, explorer window, opens on top of everything.
You can use.
Winkey + M to minimize all
Winkey + shift + M to restore all
Or
Copy and paste the following into a text file and save it as ShowDesktop.vbs. Then create a new shortcut linked to this file.
Set Shell = CreateObject ("Shell.Application")
Shell.MinimizeAll
Set Shell = Nothing
and
Copy and paste the following into a text file and save it as RestoreAll.vbs. Then create a new shortcut linked to this file.
Set Shell = CreateObject ("Shell.Application")
Shell.UndoMinimizeAll
Set Shell = Nothing
For the "off" button;
Download CloseWin http://www.tsoftcentral.com/tools/index.html and link to that.