Attempting to access another computer from My Network Places that is on a workgroup (not domain) results in the following error:

"\\<computer> is not accessible. You might not have permission to use this network resource. Contact the administrator of this server to find out if you have access permissions. Logon failure: the user has not been granted the requested logon type at this computer."


Download the following and install it

Windows Server 2003 Resource Kit Tools

after installation is complete, click on: Start, All Programs, Windows Resource Kit Tools, Command Shell

Then enter the following commands. (Attention: they are case sensitive.)

net user guest /active:yes
ntrights +r SeNetworkLogonRight -u Guest

ntrights -r SeDenyNetworkLogonRight -u Guest

The first command enables network access for Guest, the two subsequent ones change two different policies to allow network access for Guest.