Microsoft Office accessing network folders

I have a client having an issue browsing her network within microsoft office 2000. She is on Vista and when she goes to attach an email, open a file within any office program it locks up when she clicks on any folder on her network. It usually locks up totally and I have to kill the process but sometimes the folder will pull up within 10 minutes or so. Everything is fine when I browse the network using windows explorer and other apps on the computer. It's just when she is in an Office program. The first thing I did was map a network drive to the folder on the network she went to the most and that worked fine but then when she clicked on any folder within that network drive it locks up again. I have tried lots of things like disabling ipv6 but still no luck. Anyone have any advice for me?