Can't access Mavis Beacon in Guest account

[Sarah]

Hi,

I have a network of 4 computers running Win XP Pro. Mavis
beacon was operating properly. Then I set up an
Administrator's account and a Guest account to limit users
from making changes to the system. Now the Guest account
can not access Mavis Beacon. I can't even access the files
to make a desktop shortcut, because it is not allowed.

How can I permit guests (students) to access Mavis Beacon?

Thanx,

Sarah