That the startup group has 2 sources. One is YOUR account and the other is allusers.

Example:

C:\Users>dir /a
Volume in drive C has no label.
Volume Serial Number is CECD-F2B1

Directory of C:\Users

10/30/2009 10:40 AM <DIR> .
10/30/2009 10:40 AM <DIR> ..
07/14/2009 12:08 AM <SYMLINKD> All Users [C:\ProgramData]
07/14/2009 02:12 AM <DIR> Default
07/14/2009 12:08 AM <JUNCTION> Default User [C:\Users\Default]
07/13/2009 11:54 PM 174 desktop.ini
11/07/2009 03:27 PM <DIR> Public
11/10/2009 02:02 PM <DIR> wincnet
1 File(s) 174 bytes
8 Dir(s) 192,819,957,760 bytes free

C:\Users>

Explore each users home and startup groups.