Here's a quick Powershell one-liner to start up all the necessary Exchange Services for any given role.
Test-ServiceHealth | Select-Object -Expand ServicesNotRunning | Start-Service
There is also the old standby:
Get-Service *Exchange* | Start-Service
But that one can start unnecessary services (set to manual) like the Exchange Pop3 and Imap4 service.
Just thought it'd make and interesting post because not too many people know about the Test-ServiceHealth cmdlet.