How to upgrade windows 2000 domain controller to windows 2008?

Giganews Newsgroups
Subject: How to upgrade windows 2000 domain controller to windows 2008?
Posted by:  stevehunter…
Date: Sat, 14 Jun 2008

We are running a simple domain controller on windows 2000 and have a
second server that is windows 2000 (backup domain controller) that
also runs our exchange server (very old version, 5.5).

For us, this is a "once in five year" upgrade.  We only do it because
all of this technology is becoming end of life.

I have been instructed to upgrade our domain controllers to windows
2008 and install the latest exchange server and upgrade that.

So first things first, what I want to know is, what is the best path
for this?  We have about 100 exchange users (so 100 users in active

Do I:
1. upgrade the domain controllers to windows 2008, have the exchange
server (running 5.5 and windows 2000) use this upgraded domain
2. install a fresh domain and fresh exchange server and manually add
all the users
3. is there a middle ground somewhere here?

my concerns:
If I upgrade to a 2008 domain and I make a mistake and can not attach
the windows2000/exchange5.5 server to the new domain, then I am in big
trouble because our mail servers will then be dead.  has the domain
controller technology evolved that this can be an issue or will the
windows2000 server work just fine if i upgrade the domain?

What are the steps, i have googled for detailed instructions and can
not find any.  Does someone have detailed instructions on how I will
do this?  what happens to the servers that are pointing to the Windows
2000 DC, do they just continue to run and point to the new DC or do
they need to be rebooted or reconfigured?  We still have a lot of
windows 2000 servers that are destined to be upgraded as well.