virtualbox.org

I can't use UNC to access any network files while on the guest machine. I'm using virtualbox 3.1.0 with windows XP pro host and guest. I do have a connection. I can browse the internet just fine, and I can get to network files using shared folders, but I just can't seem to resolve anything with UNC.

I did some searches and couldn't find anything on how to set that up properly. If there's some help somewhere I could get redirected to, that'd be great.

Are you using NAT for the virtual NIC?
If you have a router switch to Bridged and if not select host-only for the first adapter and then add a second one set to NAT for the Internet.
Be sure that both of the Windows machines are in the same workgroup as well.