When you are connected to a windows machine via Remote Desktop (RDP), restarting the remote machine option is not present in Windows Start menu. Only options you see are Disconnect and Log off. If you need to restart that machine you can not press CTL + ALT + DEL. If you do it will bring up shut down option dialog box for local machine. So to restart Windows machine via Remote Desktop, you need to use CTL + ALT + END keys.