When you move programs around in your WindowsXP start menu, the OS will stop arranging it when you add new software. This happens when you move items from your user start menu to the all users start menu. Here is the fix:
1. Open regedit (Start -> Run. Type regedit)
2. Navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\ Explorer\MenuOrder\Start Menu\Menu OR HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\ Explorer\MenuOrder\Start Menu2\Menu
3. Remove the order key by right clicking and going to delete.
4. Log out then back in.
I wish they would include a feature that was in Windows 2000 that let you resort the start menu!