I tried to help out my father, but was unable to fix this: For his account the start menu pinned and recent programs disappeared. Programs can only be started by links on the Desktop or by going via "All Programs".
The answer from this question does not help in any way: Putting Firefox and Thunderbird into the "Show on start menu" panel has no effect. Funny enough, when going there again, both checkboxes are unchecked again. wTF?!
Any idea how to fix this?