I use Ubuntu, actually I'm using it in my work, and my computer coexist with two Windows XP machines, because I'm web engineer and we must share files every-time.
I'd installed samba because without samba i can share files, etc, but my workgroup differs from XP boxes workgroup but with samba i can see the machines with the same workgroup.

Ah, i remember that 3 months ago i had a problem like the yours, but it was the xp box that having problems.

Linux is based on unix and this is a Net Based OS (instead of windows that is designed for personal use) and Linux is very advanced for net use, but if you installed samba with a GUI interface for configuring, you need to make a little of configuration, is much better using the GEDIT over the config file, because you need to change only 2 things.

And other thing, think about it... Ubuntu doesn't need anti virus and the security things like introducing the root password are a little comparised with windows vista

Sorry my English! XD
Try to use Ubuntu, and if you want a more powerfull unix free of charge use Debian (linux is based on debian)

OMG! You've made a big mistake. Expect the usual linux fanboys horde coming your way! :)