Does it appear in your startup folder - if so just move it to hers - if not run msconfig, in the "startup programs" tab you will see the item listed - uncheck it then goto her startup folder (not msconfig) and add a short cut similar to that which appeared in your msconfig folder. - when you reboot to your account tick the box not to receive the message that you have changed msconfig info.
There is a way of doing this in the registry but the above is the simplest if you not an experienced user.
Peter