Hi,
In Windows, it’s not possible to add separators manually in the Start Menu list. The separators which are present is by design. However, if you want you may reduce the recent programs & add pinned items to the start menu by customizing the start menu.
For more information refer this link.
Customize the Start menu
http://windows.microsoft.com/en-US/windows7/Customize-the-Start-menu
Hope the information helps. Please post back and let us know.
Regards
Debleena S
Microsoft Answers Support Engineer
Visit our Microsoft Answers Feedback Forum and let us know what you think.