If you wanna shutdown or logoff your pc then you have to click Start MEnu first and then chose your option from there.
JumpControl, made by ProtoSphere, is a portable and free app which allows its users to put Shutdown, Restart, Sleep, Switch User, Lock and Log Off Options in Windows 7 taskbar.
As it is a portable app so you dont need to install it,Just extract the files from ZIP and the simply run EXE file.
You may pin it to the taskbar by draging EXE to the taskbar Or just Select Pin To The Taskbar from context menu.
You may use following link to download :-