Setup.com /M:RecoverServer

To recover a server first reset computer in Activity Directory and re-add to domain under same name (Make sure you Reset and not delete)

The run Setup.com /M:RecoverServer on server to recover.

Also View and READ these:
http://www.msexchange.org/tutorials/Recovering-Exchange-2007-Server-RecoverServer-switch.html
http://technet.microsoft.com/en-us/library/dd638206.aspx

(Hub Transport Server role installed, and this is the only Exchange 2007 Server with this role installed, it's recommended to run Setup.com /M:RecoverServer with the /DoNotStartTransport syntax, as there are a few post-recovery steps that should be completed before this role is made active.)

Errors i received:
- Setup previously failed while performing the action "DisasterRecovery". You can't resume setup my performing the action "Install"
- Setup previously failed while performing the action "Uninstall". You can't resume setup my performing the action "Install"

The problem is that exchange thing he is in a DisasterRecovery, but he isn't ??? To solf this issue:
- Start regedit
- Goto HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\ExchangeServer\v14.0\roleName
Here is the place that exchange says: DisasterRecovery. Just remove the key and try it again.