Windows 7- Disable the automatic submenu expansion option
By default in Windows 7, when you hover your mouse pointer over the "All Programs" menu or other defined menus in the Start Menu, after a brief moment Windows automatically opens the submenu. This assumes that whenever you hover your mouse pointer over a menu, you mean to expand it.
If you do not like this behavior it can be disabled.
1. Right-click an empty area of the taskbar and choose "Properties".
2. The "Taskbar and Start Menu Properties" multi-tabbed dialog box appears. Click the "Start Menu" tab.
3. Click the "Customize" button.
4. The "Customize Start Menu" dialog box appears. Scroll down and uncheck the "Open submenus when I pause on them with the mouse pointer" box.
Disable automatic submenu expansion in the Start Menu upon mouse hover in Windows 7