You don't need samba for a Linux box to "see" any Windows partitions, so I wouldn't assume that samba is set-up. I don't use Ubuntu either, so I'm not sure if the packages are installed by default (although a quick Google suggests it's not).
Samba effectively turns your Linux box into a Primary Domain Controller (PDC) that your Windows machine(s) can then use to access files and other resources.
Cobbydaler's link is a good one, but you might like also to read this one...
http://www.linuxhomenetworking.com/w...a#Introduction [linuxhomenetworking.com]