Ok, so you want to install Exchange? Well there are a few basic rules of Enagement.
1) Never, Never, Ever use the GUI to install any exchange role or you'll end up hacking out the installation.
2) Don't install updates as part of a service pack or base installation.
Basic Setup Commands
Installation Prerequisites for Windows Server 2008
Exchange Client Access Server
ServerManagerCmd -i PowerShell
ServerManagerCmd -i Web-Server
ServerManagerCmd -i Web-ISAPI-Ext
ServerManagerCmd -i Web-Metabase
ServerManagerCmd -i Web-Lgcy-Mgmt-Console
ServerManagerCmd -i Web-Basic-Auth
ServerManagerCmd -i Web-Digest-Auth
ServerManagerCmd -i Web-Windows-Auth
ServerManagerCmd -i Web-Dyn-Compression
ServerManagerCmd -i RPC-over-HTTP-proxy
ServerManagerCmd -i RSAT-ADDS
Exchange MailBox Server
ServerManagerCmd -i PowerShell
ServerManagerCmd -i Web-Server
ServerManagerCmd -i Web-ISAPI-Ext
ServerManagerCmd -i Web-Metabase
ServerManagerCmd -i Web-Lgcy-Mgmt-Console
ServerManagerCmd -i Web-Basic-Auth
ServerManagerCmd -i Web-Windows-Auth
ServerManagerCmd -i Failover-Clustering
ServerManagerCmd -i RSAT-ADDS
Exchange Hub Transport Server
ServerManagerCmd -i PowerShell
ServerManagerCmd -i RSAT-ADDS
Exchange Management Console
ServerManagerCmd -i PowerShell
ServerManagerCmd -i Web-Metabase
ServerManagerCmd -i Web-Lgcy-Mgmt-Console
ServerManagerCmd -i RSAT-ADDS
Exchange Setup Command Parameters