Did your Exchange server stop working out of nowhere? Here are some common troubleshooting steps:
1. Go into your services panel and make sure all of your Exchange services are started
Microsoft Exchange Event
Microsoft Exchange IMAP 4
Microsoft Exchange Information Store
Microsoft Exchange Management
Microsoft Exchange MTA Stacks
Microsoft Exchange POP3
Microsoft Exchange Routing Engine
Microsoft Exchange Site Replication Service
Microsoft Exchange System Attendant
2. If you are unable to start any of these services you need to check two things
Make sure your antivirus has not quarantined anything in c:prgoram filesexchsrvr
Make sure your hard drives have not ran out of space