Your smb.conf looks fine to me, except I would uncomment this line
workgroup=workgroup on Windows box as well?
to create a new samba user and password on your linux box try this from terminal as root
# smbpasswd -a "your user name no quotes"
I like to have all these installed:
If your attempting to browse windows files with samba and nautilus make sure you have libgnomevfs2-extra installed.
Here's a good guide to network printing:
Here are a couple of commands I found helpful for printer config
To get a list of the share names on a Windows computer
smbclient -L "your windows box name, no quotes"
To get a list of Netbios names on your network type
nmblookup -S MSHOME
I was miss-identifying hardware and share names in cups when setting up remote printer.
I believe the "invalid user=root" is a security measure. You wouldn't want someone accessing your machine as user root through samba.