Prior to that can you please post your smb.conf ?
or if you just want it for some test purpose, you can also set your samba as
netbios name = shemp
workgroup = stooges
map to guest = Bad user
path = /<path-to-share>
read only = no
guest ok = yes
You do not need any user to be added if you are going to follow the above mentioned smb.conf (for test purpose only)
or otherwise you got to add users via
to unix passwd database & then the same username to samba password database by
Yes you can keep your windows & linux user & pass same for easier access.
You should also check http://amitsharma.linuxbloggers.com/how_to_samba.htm
for further reference.