Profiles

I have a Windows 2003 server and over 3000 accounts. The problem that i have is that every time someone login to a computer it takes from 5-30 minutes for the system to create a profile. We have copy the main profile to be the default user, changed the restriction set everything the way we wanted. We have a program that freezes the computers so that there is no files change or other profiles to be stored in the computer. Is there a way in wich we can speed up the loading process for our users? If you need more info feel free to ask. Thanks in advance