Windows Media Player 11 and VCD

Okay i got this weird stuff going on in my PC

1st of all I use vista 32 bit, and i have two accounts on my PC, one for me and one for my guest. So one day my guest (mom) decide to use my ub3r gaming PC to watch VCD for some reason. As she put the disc in, nothing happened and the media player doesnt seem to work. Okay, so later when i came back from school and practice and JROTC meeting, i used my account to run that VCD and miraclely it WORKED! (for some reason again)

can someone tell me what is wrong with the other account and how can i make the media player on the other account play VCD movies? I do not want the 'guest' bothering me. i need to study for my career! :major