How to Enable or Disable Pinning and Unpinning of Items in Windows 7 Jump Lists
This will show you how to enable or disable the ablility of users to pin or unpin items, such as recent and frequent items, files, folders, and websites, to or from Jump Lists in the Start Menu and taskbar in Windows 7.
You must be logged in as an administrator to be able to do the steps in this tutorial.
On a computer that is running Windows 7 or Windows Server 2008 R2, the Jump List of an application may disappear permanently when you use the application to open or save a new item. This issue occurs when there are 999 items in the Jump List already.
Installing the update at the link below resolves the issue and enables the displaying of the Jump Lists.