XP Slow to Logon

I recently upgraded my network to a windows 2000 domain. I have a mix of Win98, Win2000 and Xp workstations. I have enabled active directory on my domain controller but have not configured a DNS server as I’m still using WINS for name resolution. All workstations but XP have no problems – I have 4 machines running XP and they are all extremley slow to logon and constantly lose network and printer connections. I don’t have any group policies enabled and it doesn’t make a difference who logs on to the machines. I am guessing it may have something to do with dns resolution as the only dns servers specified are external. Any ideas?