When in doubt (about whether or not file-sharing is set up correctly or not) try accessing the "admin-share" created by default when file-sharing (the server service) is enabled.
Open "My computer"
In the address bar type " \\xxx.xxx.xxx.xxx\c$ " (the xxx.xxx.xxx.xxx is obviously the correct IP address of the computer you're attempting to access.
The above will attempt access to the "admin-share" on said computer. You will be asked to supply the correct ADMIN credentials to connect (ie. the admin account info of that computer).
If that works, then your problem is likely a permissions one. If however that doesn't work, then it may be a firewall or other network setting (ie. network discovery etc.)
Post back with more info and we'll be glad to keep helping.
thanks,
the Monk