1. Stop the IS, then move or copy your databases to another location.
2. Shut down the server
3. In ADUC, reset the computer account.
4. Insert the windows CD and power the server on. wipe the old volumes and do a fresh install using the same name?IP. Join the domain.
5. Install hotfixes service packs as the original.
6. Install exchange with the /disasterrecovery switch. Install all the dame hotfixes/service packs.
7. Down the IS, then copy/move databases and logs back to their original locations. start the IS.