Open file dialogue soooooo slow when offline

Guys,

I have a laptop running Windows XP sp2. At work this connects to the
work's domain and performance is fine.

I have offline files on a number of shared drives that I need when out
and about.

However, when working at home or disconnected from any network, the
open file dialogue in any Office program takes a very long time to
show a list of folders when you click "Look In". Then choosing a
folder to expand takes a long time as well. I am talking minutes per
action!

I discovered that if I run "ipconfig /release" before or during the
wait, everything becomes extremely responsive. However once I renew
the network connection - everything is very slow again.

The machine also has another local user - this has no files or drives
mapped and works great when disconnected or connected.

Does anyone have any idea - at present I am releasing my network
everytime I want to open a file - ridiculous!!

TIA

Graham