Too slow to login to windows 2008 domain

We are using windows 2008 server based domain
and when we login to this domain from XP
systems it will take 10 minutes to complete the
login process.It goes to the login screen OK
but when a username and password are input, it
takes 20 minutes to login in. Its stays on
‘checking network connections’ and ‘ applying
security settings’ for a while.My dNS entry is
correct in client system

can anyone help me to solve this problem