Vista just stopped working with Samba, XP still works fine

Vista just stopped working with Samba, XP still works fine

I run Ubuntu in a VirtualBox for web dev at work. I installed Samba on it so I can access it from various computers. Today I came into work as usual and the Vista(Host) machine can't connect to Samba anymore... My laptop... the one I bring from home... that runs XP is able to connect just fine.