[ubuntu] Samba not coecting with new client

hi,
I am using samba on my server. There are 15 users which are already coected with the samba server to share their files. The problem is, in a fresh windows installation ( windows 7 ) i can not access my samba server share folder.In windows 7 the firewall is off,it can ping the server as well. Well on the client windows 7 it takes 3 to 5 minutes after writing the private IP address on my samba server,I write the user name and its password then it show me "No rights".
I did the same practice with two different computers which which fresh windows install but i face same problem.

On the other hand my ruing client computer can access with the same user name and password and I can access the samba share folders.

please guide me how can I fix the problem.

thanks,
gardenair