From what information you posted it doesn't sound like a Samba issue but a Networking or a name resolution issue. There's an easy way to find out. Run the following command:
Change 192.168.0.100 to the ip address of the Windows machine.
If you can get through then Samba is working just fine.
As far a seeing your Windows machine by name in Nautilus there's really only a number of things that can get in the way:
** Can't browse by name unless all the machines are in the same subnet so check your ip addresses and see if they are in the same subnet.
** Some or all of the samba dependent services aren't running so check them and if they are not started start them:
** Firewall is in the way so temporarily stop it:
sudo service smbd start
sudo service nmbd start
** The default mechanism to convert netbios names to ip addresses is being foiled by "wins".
Linux and Windows will both default to broadcasting their names to one another but on Linux it gets messed up but Samba allows you to prioritize this by adding an option - right under the workgroup line in /etc/samba/smb.conf:
Then restart smbd and nmbd again.
name resolve order = bcast host lmhosts wins
But I tell you life is short so if you keep having issues with Samba / Networking then why not set the Windows machine to have a static ip address and access it that way. You can bookmark it in Nautilus when you get access so you don't have to remember it's address.
I just set up a home network for someone with Win / Lin / OSX / iOS components and the easiest thing is to add the following utility to the Windows machine: http://support.apple.com/kb/DL999 . And make sure port 5353/udp is open.
Despite it's name what it does is install the Windows equivalent of Avahi ( Bonjour in Apple products ). From that point on you access it by it's host-name.local regardless of it's ip address at that moment and then bookmark that if you want:
Linux and OSX respond to *.local queries by default and with the added package so will Windows.