On XP anyway.
right click "Start" select "properties". Now you should have a box that says "Taskbar and Start Menu Properties" with the start menu tab opened.
Select "Customize" on the right of the box.
Now you have "Customize Start Menu", with the General Tab open.
Select "Clear List" on the right side again, in the programs section. You can also determine here, the number of programs shown in your start list.
BTW these are only shortcuts to recently used programs.
If I'm understanding your post right, this is what your looking for.