Removing an additional domain out of AD and Exchange

Would following the steps below be the only procedure to take?

http://support.microsoft.com/?id=230306

KB is ok, but use the DCPROMO to do it. As mentioned in the KB. Meta cleanup is the last option. If you can share the design. Will review it again. If any change required will let u know.

I found that the article does not do what I wanted it to do. When looking for the domain, it does not pull up it only shows my primary domain.

Question: Can I just go to the OU in AD and delete the domain, remove all addresses in DNS, and unmount the database in exch 2010?

Deleting OU will not going to cleanup the AD or Exchange. Remove AD or Exchange is different process.

For AD removal , DCPROMO is the only command or metacleanup. With DCPROMO you can use /forceremoval if DCPROMO is not allowing to remove. Later clear it from AD and DNS also

For Exchange, first option is to use ADD/Remove program. If you want to remove it manaully follow below article.

http://www.windowsitpro.com/article/exchange-server/How-to-Uninstall-a-Stubborn-Exchange-Server.aspx

Without seeing the design, I cannot say 100% u need to do this.

Thanks, but "I think" this is more than I need. The domain is just an additional domain that we added by creating an additional OU, adding IP's in DNS and pointing the MX records to our exchange. The company is moving their services, so we no longer need to support their exchange.

At this point, if we email their domain, then the emails fail because DNS is pointing to our server (I just deleted their records in DNS). I need to remove their OU and their records to clean our Active directory. Do you think  I need to run DCPROMO to remove an additional domain?

I am bit confused with OU part. If you can paste some screeshot, will see them

Well the problem I'm having is that I cannot email them. The domain is alive on a different server, but I'm trying to eradicate the issue of not being able to email them.

Thanks for your help Amitkulsh... I actually had to go into ASDIEdit to get rid of it entirely. I couldn't remove it without doing so.