This is a small-office print network printer puzzle:

Given: All PCs are running WinXp Pro. One machine has a printer attached and shared on a network. This machine and all client PCs are in same workgroup. Printer is shared with permissions set very loosely so that "Everybody" has full access for printing docs and managing printer. No domain controller.

Problem: Users on client PCs on the network who do not _also_ have an account on the "print server" machine cannot access the printer. No capability to anonymously print documents. A user logged into a client PC who also has a an account with same user/password combo on the "print server" machine can print OK.

Clues:
1. When a user unknown to the printer server machine browses "My network places" and tries to access resources on the "print server" machine, a login challenge is presented as soon as that machine is clicked in the treeview. No capability to see if any printer resources are attached to the machine, much less access such a resource.
2. HOWEVER, if at the outset the anon user happens to know the name of the "print server" machine and its printer share, then that user can install the printer using the "Add printer" dialogue. Install seems to work fine. It's accessing it that isn't allowed.
2. Guest account is disabled on the printer server machine.

Attempted fixes:
1. For the shared printer's permissions, gave "full control" to "Everybody". Made no difference.
2. In local security policy, set behavior to treat anonymous logins as "Everybody". Made no difference.

What's the problem, and what is the fix, to allow users on the LAN unknown to the "print server" computer to still print to its shared printer?

Thanks!