Extremely Slow Logins

I have a few accounts and computers that take up to 20 minutes to login. With a couple accounts it is on every compter on the network; with others it is just a few random computers. I have some accounts that login w/o incident on all computers so I am having a tough time narrowing down the problem and finding a solution.

Any suggestions?

 

more information is required. Please provide the type of network, NOS used, workstation OS used etc.. thank you

 

Sorry I forgot those details. Active Directory on Win Server 2003 on the server and Win XP Pro on all other machines. It is all connected via 10/100 ethernet. The problem comes when connecting to the domain on boot

Anything else that will help?

 

how big are the profiles of those that are loading slow?

 

Two services can really slow things down. NET LOGON and NETWORK LOCATION AWARENESS.

Both seem to be on automatic startup as default. I disabled both and brought login to <30 secs vs from around 180.