You do need to be logged in as Administrator then do the following:
Go to Start, Run and type mmc
This will start the Microsoft Management Console. On the Top Menu click on File, Add/Remove Snap-in. Click the "Add" button. Scroll down and double-click "Group Policy Object Editor", then click the "Finished" button. Click the "Close" button then the "OK" button in the Add/Remove Snap-in dialogue.
Expand the tree by clicking the plus signs to the left of Local Computer Policy, User Configuration, Administrator Templates and then click on "Start Menu and Taskbar"
Scroll down the list on the right until you find "Prevent changes to Taskbar and Start Menu Settings" and "Remove access to the context menus for the taskbar". Double-click each of these in turn and set them to Disabled. Close down Microsoft Management Console. There is no need to save.