after configured AD startup proccess very slow in my windows server 2003

I am

having problems with the DC?s because they use near 25 minutes in the

startup proccess (In preparing for network connections and Applyng Server

Policies) after that, the logon screen appear.

I have not this problem in the servers that are not DC?s

Several services like DNS and DHCP said, after the startup proccess end,

that they can not access to the Active Directory for authentication and

the

event log suggest me to check if AD is working ok.

I have no problems with users logon in the AD.