Vista - Always need password for network

Vista Home Premium desktop and notebook.
When using Network to access the Public folders on the other computer it always asks for a password.
Password protection is turned OFF on both.
The user thinks her son deleted the Guest accounts. IS this possible?
If so how can I reinstate the guest accounts?

In Sharing>>Permisions .Does Everyone have access to this folder?

You can't delete native build-in accounts or groups -surly you have only Guest account disabled.You can turn account in many ways for example Control Panel>>User Accounts...

EDIT
See also:
File Sharing - Turn On or Off
Simple File Sharing - Enable

easier solution go into the network and sharing center and turn off password protected sharing

check the following:
right click on the folders in question, go to properties, go to the security tab, at the top there should be a list of users.... make sure that the user "everyone" is in there. If that user isn't there, then that's the problem. You should add that user. Also, make sure you give that user the proper rights.
Even with the password protected sharing turned off, if the user everyone isn't in that list, it may cause a prompt for a password.