How to Restart a Microsoft Exchange Server
The Microsoft Exchange Server holds all the mailboxes and mailbox data in your company or organization. For various reasons, you may experience server outages or server crashes. Most of these issues can be fixed by simply restarting its core data storage repository, "Microsoft Exchange Information Store" service.
Login to a PC server computer with administrative privileges.
Click Start and select "Run..." Type without the quotes "services.msc" and press "Enter."
Locate "Microsoft Exchange Information Store" service under "Results."
Right-click the service and select "Restart."