Is it possible to put dividers in the Windows 7 start menu? If so, how?
I'd like to put dividers in the same location as the red line.
The only way to regain the control over the Start menu which was available in previous versions of Windows before 7, is to use an alternative third-party product. Most of them can either replace or run side-by-side with the original Windows one.
Start Menu 7 (free, Pro version $19.99)
Aston Menu ($19.95)
Start Menu Organizer (free, Pro version $19.95)
Not all the products answer exactly your question of the separators, but they certainly allow organizing the Start menu in more ways than does Microsoft.
The only divider possible is the one that splits the lower dynamic program listing from the upper items pinned to the start menu.
Right click one of the top apps you highlighted, select 'Pin to Start Menu' and it will be automatically placed above a divider line.