Win XP clients taking ages to logon

We have a Windows 2000 Server and have recently connected a few windows XP PC’s to it. We have had huge problems logging in to the network as the PC’s sit with “Applying policies” etc. but do not login for over 25 minutes.

I rebuilt one of the PC’s but this did not work and decided to rebuild the server which also did not solve the issue!

We have had to logon to the PC’s locally as it is too disruptive to use with the network login but this defeats the whole purpose of having the network!

Any help would be greatly appreciated.