Replacing Exchange Server

I am in the process of replacing the Exchange server. I wanted to get some feedback to see if there may be an easier way than I am looking at. It is the domain controller, and exchange server. The current server is running out of room on the system partition and the hard drive has bad sectors. There is a 2nd server that is a file server I was going to run dcpromo on it so that it would be a second domain controller and have a copy of AD and become the PDC on the exising box went away. I have named the exchange replacement the same name since it is for internal and external email. It is currently not on the network. I was going to leave it off until I could switch to avoid conflict. I also have backups of exchange to restore mail.